Monthly Archives: March 2025

　　The image above is from the crowdfunding project ＾Neosegment Digit￣ by Maks Surguy on Crowd Supply. The project has gained significant attention, raising a total of $6,500. We are proud to support Maks in assembling this project.However, with the development of the industry, FLEX PCB It will also bring us more and more consumer experiences, so that users can really feel the upgrade and change. https://www.wellcircuits.com/

　　

　　Wellcircuits has also assisted creators with the assembly of the following projects on Crowd Supply:

　　

　　ALio Proto Board: The All-in-One Prototyping Board

　　

　　Neosegment Digit

　　

　　Paperino

　　

　　Crowd Supply is a popular crowdfunding platform based in Portland, Oregon, known for supporting creators in bringing innovative and useful hardware to life. Their mission is to provide the necessary funding and resources to help creators deliver high-quality products to their backers.

　　

　　We first met at the 2017 Open Source Hardware Summit, where we discussed the potential for future collaboration. Both of our goals are aligned in helping enthusiasts bring their projects to life. Today, we are excited to announce our partnership:

　　

　　Any successful crowdfunding project on Crowd Supply is eligible for a 10% discount (up to $300) on PCB assembly services at Wellcircuits. You can also apply for a coupon code for your backers. Simply send your project link to anson@wellcircuits.com to receive your discount.

　　

　　As a professional PCB production and assembly company, Wellcircuits has earned a strong reputation among engineers worldwide. This partnership will leverage our strengths to ensure smooth execution for crowdfunding projects. All of our components are original, and we guarantee on-time delivery, ensuring your supporters receive their products as quickly as possible. Additionally, you can count on excellent after-sales service at Wellcircuits.

　　

　　Let¨s create something amazing together!

　　What is a fixed-frequency air conditioner? The grid voltage in China is 220 volts and 50 hertz, and the air conditioner working under this condition is called a fixed-frequency air conditioner. Because the power supply frequency can’t be changed, the rotating speed of the compressor of the traditional fixed frequency air conditioner is basically unchanged, and the indoor temperature can be adjusted by constantly “turning on and off” the compressor, which is easy to cause the room temperature to be hot and cold and consume more electricity.If you want to make a big difference in the market, Puremind Commercial Air Conditioners It is necessary to intensify the upgrading of products on the original basis in order to meet the consumption needs of consumers. https://puremind.com/puremind-hot-sale/

　　

　　What is a variable frequency air conditioner? The main engine of the variable frequency air conditioner automatically performs stepless speed change, and it can automatically provide the required cooling (heating) amount according to the room conditions. When the indoor temperature reaches the expected value, the air conditioning main engine will run at a constant speed that can accurately maintain this temperature, so as to realize “non-stop operation”, thus ensuring the stability of the environmental temperature.

　　

　　Advantages and disadvantages analysis:

　　

　　Advantages of fixed frequency air conditioning: affordable price, more options, rich products and various types.

　　

　　Disadvantages of fixed frequency air conditioning: Relative temperature control and energy saving are still slightly inferior to frequency conversion.

　　

　　Advantages of inverter air conditioner: more accurate temperature control, low temperature, wide voltage start, and more energy saving.

　　

　　Disadvantages of inverter air conditioner: the relative price positioning is higher, while the affordable inverter is less optional.

　　

　　To sum up, it is obvious that inverter air conditioners are smarter! But the price will naturally be more expensive.

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According to a report by India’s Politico on March 15, the Bombay Stock Exchange Sensitive Index (SENSEX) and N Index fell for the first time in a single week after rising for four weeks. Both indices fell about 2% this week, the biggest weekly decline in 20 weeks.

The SENSEX index fell 062% on the day to close at 7264343 points. The N50 index of the National Stock Exchange of India (NSE) fell 0.56% to close at 2202335 points.

The Bombay Stock Exchange (BSE) mid-cap index also closed down 0.51%. However, the BSE Small Cap Index bucked the trend and closed up 0.25%.

On the weekly chart, the benchmark SENSEX index fell 22% for the week and the N index fell 21%. This is the largest weekly decline since October 2023. The BSE mid-cap and small-cap indices fell about 4% and 6% respectively this week.

From an industry perspective, the N-Metal Index and FMCG Index closed flat, while all other industry indices closed down.

The biggest declines were in the oil and gas industry and the automobile industry, with declines of 198% and 157% respectively. The N Bank index fell 0.42%.

As some funds release stress test results, they are confident that their portfolios can cope with volatile market conditions.

In global stock markets, the weakness is believed to be driven by discouraging U.S. economic data and weakening expectations of a Federal Reserve interest rate cut.

Some reports showed that the U.S. industrial producer price index (PPI) exceeded expectations in February. At the same time, the number of people applying for and receiving unemployment benefits was lower than expected. These factors weaken the Fed’s case for interest rates.

Market participants will be closely watching the Fed’s monetary policy stance next week. Most expect the Fed to keep interest rates unchanged and start cutting rates from the end of June or July. (Compiled by Zhu Jie)

　　Central air conditioning is an indispensable energy consumption operation system in modern buildings. Central air conditioning system not only provides people with comfortable living and working environment, but also consumes a lot of energy. According to statistics, the energy consumption of buildings in China accounts for about 30% of the total energy consumption. In buildings with central air conditioning, the energy consumption of central air conditioning accounts for about 70% of the total energy consumption, and it is increasing year by year. Therefore, how to efficiently use the energy and energy saving of central air conditioning system has become an urgent problem to be solved.So, I believe split system hvac In the future, it will be promising to create a miracle belonging to the industry. https://puremind.com/product-category/puremind-air-conditioner/split-air-conditioner/

　　

　　The normal operation of the central air conditioning system, its energy consumption mainly has two aspects [1″ target=_blank>: on the one hand, it is the energy consumption of cold and heat sources to supply air handling equipment with cold and heat; On the other hand, in order to transport air and water, fans and pumps need energy to overcome the flow resistance. The energy consumption of central air conditioning system is affected by many factors, and many operation links have energy-saving measures. Therefore, energy-saving of central air conditioning is a comprehensive project. The following introduces several commonly used energy-saving measures in terms of energy consumption of cold and heat sources and power consumption.

　　

　　1. Energy-saving measures for cold and heat sources

　　

　　1.1 Temperature and humidity control

　　

　　From the air treatment process of central air conditioning system, it can be seen that the lower the indoor temperature and relative humidity in summer, the greater the energy consumption of system equipment; The higher the indoor temperature and relative humidity in winter, the greater the energy consumption of the system equipment, and the corresponding initial investment and operating costs also increase.

　　

　　Because everyone’s requirements for comfort are very different, there can be a wider comfort zone for civil central air conditioning. In this comfort zone, when cooling in summer, take a higher temperature and humidity value; When heating in winter, a certain energy-saving effect can be obtained by taking a lower temperature and humidity value. The change of temperature and humidity in the building is closely related to building energy saving. According to empirical statistics, if the set temperature is lowered by 1≧ in summer, the energy consumption will increase by 9%. If the set temperature is raised by 1≧ in winter, the energy consumption will increase by 12%. Therefore, it is an effective measure to control the temperature and humidity in the building within the precision range of the set value.

　　

　　In order to reduce energy consumption, the indoor temperature and humidity base of air-conditioned rooms should be raised as much as possible in summer and lowered as much as possible in winter under the condition of meeting production needs and human health. At present, some owners blindly pursue the realm of “cold enough” and greatly improve the design standard of indoor temperature and humidity, which not only wastes a lot of energy unnecessarily, but also produces the negative effect of comfort.

　　

　　The higher the temperature and humidity control precision of air conditioning system, the better the comfort and the more obvious the energy-saving effect. The accuracy of the signal measured by the front end of the air conditioning system directly affects the precise control degree of the central air conditioning system. Therefore, the measured signals, especially analog signals such as temperature and humidity, must be as accurate as possible.

　　

　　Also, BAS with high control accuracy must be selected to control the central air conditioner. Because BAS uses DDC (Direct Digital Controller) to directly control the opening of electric water valve without intermediate regulator; In addition, DDC contains a wealth of calculation and control software, such as PID algorithm, fuzzy control algorithm, genetic algorithm and so on, to ensure the control accuracy.

　　

　　1.2 cold source efficiency control

　　

　　The performance index to evaluate the refrigeration efficiency of cold source is COP (Coefficient Of Performance). Refrigeration coefficient refers to the amount of cold energy that can be obtained per unit power consumption. The refrigeration coefficient has nothing to do with the nature of refrigerant, but only depends on the temperature T0 of the cooled object and the coolant temperature Tk. The higher T0, the lower Tk and the higher the refrigeration coefficient. So don’t make the chilled water temperature too low and the cooling water temperature too high during the actual operation of the air conditioning system, otherwise the refrigeration coefficient will be low, which will consume a lot of work and high power consumption to produce unit cooling capacity, and increase the energy consumption of the building. The following measures can be taken to improve the efficiency of cold source:

　　

　　1) reduce the cooling water temperature

　　

　　The lower the cooling water temperature, the higher the refrigeration coefficient of the cooler. For every 1≧ increase in the supply temperature of cooling water, the COP of the chiller decreases by nearly 4%. To reduce the temperature of cooling water, it is necessary to strengthen the operation management of cooling tower. First of all, for the cooling tower that stops running, the valves in and out of the water pipes should be closed. Otherwise, because the water temperature from the stopped cooling tower is high, the temperature of the mixed cooling water will increase and the refrigeration coefficient of the cooler will decrease. Secondly, after the cooling tower is used for a period of time, it should be overhauled in time, otherwise the efficiency of the cooling tower will decrease and the cooling water cannot be fully cooled.

　　

　　2) increase the temperature of chilled water.

　　

　　The higher the temperature of chilled water, the higher the refrigeration efficiency of the chiller. When the temperature of chilled water supply is increased by 1≧, the refrigeration coefficient of the chiller can be increased by 3%, so don’t blindly reduce the temperature of chilled water in daily operation. First of all, don’t set the set temperature of chilled water of the cold machine too low. Secondly, the water valve of the stopped chiller must be closed to prevent some chilled water from taking the bypass pipeline, otherwise, the amount of water passing through the running chiller will be reduced, resulting in the temperature of chilled water being lowered to a too low level by the chiller.

　　

　　2. Energy-saving measures for power consumption

　　

　　2.1 Transportation energy consumption control

　　

　　Power consumption mainly refers to the electric energy consumed by fans and pumps in system operation. Calculation formula of input power from fan and water pump:

　　

　　(1) (W): input power; : volume flow; : indenter; Eta: efficiency

　　

　　From Formula (1), it can be seen that reducing power consumption can be considered from the following three aspects: reducing flow, reducing system resistance and improving the efficiency of fans and pumps. The following measures can be adopted in engineering practice:

　　

　　1) adopt large temperature difference.

　　

　　If the temperature difference between the supply and return water (or the return air) used to transport cold and hot water (or air) in the system is large, then when the ratio between it and the original temperature difference is m, it is known from the flow calculation formula that the flow rate is reduced to 1/m3 when the large temperature difference is used. At this time, the power required by the water pump or fan will be reduced to 1/m3. It can be seen that the energy-saving effect of increasing the temperature difference is obvious.

　　

　　On the premise of meeting the requirements of central air conditioning accuracy, personnel comfort and technology, the temperature difference of air supply should be increased as much as possible. It should be noted that the temperature difference between supply and return water should not be greater than 8≧.

　　

　　2) choose low flow rate.

　　

　　Because the power consumption required by pumps and fans is roughly proportional to the flow velocity in the pipeline system, in order to achieve energy-saving operation effect, high flow velocity should not be adopted in design and operation. In addition, the low flow rate in the main pipe is also beneficial to the stability of the hydraulic condition of the system. For example, changing the rotational speed of the fan can change the performance parameters of the fan. The power of the fan has a cubic relationship with the rotational speed, while the flow rate has a linear relationship with the rotational speed. Lowering the rotational speed can greatly reduce the energy consumption while reducing the flow rate. When the flow rate is reduced by 1/3, the energy consumption can be reduced by about 70.4%, and when the flow rate is reduced by 1/2, the energy consumption can be reduced by about 87.5%, and the efficiency of the fan is basically unchanged, and it can still work stably and efficiently.

　　

　　3) adopt energy-carrying medium with high conveying efficiency.

　　

　　Under normal circumstances, the energy consumption of transporting cold and heat energy with water is less than that with air, and the diameter of water pipes used to transport the same cold and heat energy is much smaller than that of air pipes, which occupies a much smaller building space. This is also one of the main reasons for the rapid development of central air conditioning in recent years.

　　

　　Therefore, for the centralized refrigeration mode, in principle, the chilled water prepared by the equipment in the computer room should be transported as far as possible to the vicinity or use point of each central air-conditioning partition, and the air should be treated by the terminal non-independent central air-conditioning units (such as cabinet air-conditioning units and fan coils) for local use or for use in nearby rooms.

　　

　　2.2 VAV system control

　　

　　VAV system is an energy-saving countermeasure against the shortcomings of power consumption in air supply system. VAV system can be divided into two types: one is AHU！VAV system of air conditioner; One is the indoor fan variable air volume system (FCU-VAV system) in FCU system. AHU-VAV system is to fix the air supply temperature in the whole air duct system and adjust the air supply volume of the blower to cope with the change of indoor air conditioning load. In FCU-VAV system, the cold water supply is fixed, and the indoor FCU is equipped with a stepless power controller to change the air supply, that is, to change the heat exchange rate of FCU to adjust the indoor load change. These two methods can reduce the power consumption of the blower by adjusting the air volume, and at the same time, they can also increase the operating efficiency of the heat source machine and save the power consumption of the heat source, so they can achieve energy-saving effects in both air supply and heat source.

　　

　　The cooling capacity sent into the room can be determined by the following formula:

　　

　　2

　　

　　Where: c is the specific heat capacity of air, kj/(kg≧); ρ is the air density, Kg/m3; L is the air supply volume, m3/S; Tn is the indoor temperature,≧; Ts is the supply air temperature,≧; Q is the heat absorbed (or put) into the room, KW.

　　

　　If the air supply temperature is set as a constant and the air supply volume L is changed, different Q values can be obtained to keep the room temperature unchanged. Variable air volume control can adopt an air supply device that automatically adjusts the air supply volume according to the change of indoor load. When the indoor load decreases, it can keep the air supply parameters unchanged (no need to reheat) and keep the indoor temperature stable by automatically reducing the air volume. In this way, it can not only save the reheat required by the constant air volume system to increase the air supply temperature, but also reduce the power consumption of the fan and the cooling capacity of the refrigerator due to the reduction of the treated air volume. According to various data, VAV can save energy by 30% ~ 50% compared with constant air volume.

　　

　　2.3 Frequency conversion control

　　

　　In most buildings, the central air conditioning is at the maximum load only for a few days in a year. The cooling load of central air conditioning is always changing dynamically, such as the changes of various factors such as morning and evening, climate, passenger flow and activity content, which affect the cooling load of central air conditioning in real time. Generally, the cooling load fluctuates in the range of 5 ~ 60%, and most buildings are at least 70% in this situation every year. However, most central air conditioners are driven by maximum cooling load and maximum power due to system design. In this way, the contradiction between the actual cooling load and the maximum power output is caused, resulting in a huge waste of energy. This contradiction can be solved by adopting frequency conversion control.

　　

　　1) Fan and water pump frequency conversion control

　　

　　In the past, the AC motor itself didn’t adjust the speed, so the central air conditioning system had to rely on baffles and valves to adjust the air and water flow, and a lot of electric energy was wasted on baffles and valves. If the fan water pump is regulated by frequency conversion, the energy wasted on baffles and valves will be saved, and the average energy saving effect of each pump will be considerable.

　　

　　For the fan water pump, according to the principle of fluid mechanics, the parameters under similar working conditions have the following relationship [2″ target=_blank>:

　　

　　3

　　

　　Where Q1, H1, n1 and N1 are the flow, lift, power and rotation speed before the rotation speed change, respectively;

　　

　　Q2, H2, n2, N2: the flow, lift, power, and rotation speed after the rotation speed is changed respectively.

　　

　　According to Formula (3), the flow rate is proportional to the rotational speed, the pressure is proportional to the square of the rotational speed, and the power consumed is proportional to the cubic power of the rotational speed. For variable frequency speed regulation, the speed n is basically proportional to the power frequency f, when the power frequency f decreases, the motor speed also decreases, and the required power decreases rapidly with the cubic power of the speed, which shows that the energy-saving effect is very remarkable. Take the fan as an example, if the required air volume is 80% of the rated air volume, the speed will also drop to 80% of the rated speed, and the shaft power will drop by 51.2%; When the required air volume is 50% of the rated air volume, the shaft power drops by 12.5%. This power saving effect is also very impressive. It has been proved that the frequency conversion control of fans and pumps can save energy by 40% ~ 50%.

　　

　　2) Frequency conversion control of water chillers

　　

　　Because the compressor does not rule out the possibility of long-term operation under full load, the capacity of the motor can only be determined according to the maximum demand, so the design margin is generally large. In actual operation, the proportion of light load operation time is very high. Frequency conversion control is adopted to adjust the speed of compressor, so as to control the refrigeration capacity and keep the refrigeration unit in the best (most reasonable) operation state. Frequency conversion control improves the efficiency of air conditioner and the operation effect of refrigeration unit, thus realizing energy saving.

　　

　　The principle of variable frequency compressor is to adjust the displacement of compressor per unit time by adjusting the speed of compressor, so as to achieve the purpose of adjusting the refrigeration capacity. The mathematical relationship between refrigeration capacity and compressor frequency is as follows:

　　

　　4

　　

　　Where n is the rotational speed, f is the frequency of the motor, p is the polar logarithm of the motor, s is the slip of the motor, λ is the leakage coefficient, Ps is the suction pressure, vh is the suction volume, ni is the polytropic index, εi is the pressure ratio (exhaust/suction), δ0 is the relative pressure loss coefficient, and Zs and Zd are the actual gas compressibility coefficients, which are the average energy efficiency ratio.

　　

　　According to Formula (4), the refrigeration capacity is directly proportional to the frequency, so the refrigeration capacity can be controlled by frequency conversion regulation, thus achieving the energy-saving effect.

　　

　　Some adjustment methods (such as adjusting the valve opening and changing the blade angle) can not reduce the operating efficiency of the motor even if the demand is small. After adopting frequency conversion speed regulation, when the demand is small, the speed of motor can be reduced and the running power of motor can be reduced, thus further realizing energy saving. It has been proved that the frequency conversion control of water chillers can save energy by 20% ~ 30%.

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China, March 11. According to Yonhap News Agency, in the event of a collective strike by inpatients and interns, the South Korean government will dispatch military doctors and public health doctors from the 11th to make up for medical vacancies, while continuing to send notice of revocation of licenses to doctors who have left their posts.

According to news from the South Korean government and medical circles on the 11th, the South Korean Ministry of Health and Welfare (MOHW) will dispatch 20 military doctors and 138 public health doctors to 20 hospitals across the country. These medical staff are mainly responsible for surgeries on severe and emergency patients to alleviate problems such as delayed medical treatment.

On the other hand, South Korea’s Ministry of Welfare will this week issue a notice of license revocation to residents and interns who fail to comply with the work order. South Korea’s Ministry of Welfare has sent notices to doctors who have left their posts since the 5th, and the delivery is expected to be completed as early as the beginning of this week. According to the notice, the doctor who received the notice must provide his opinion before March 25, otherwise the government will treat him as having no opinion and impose disciplinary sanctions based on his authority.

The results of a written inspection of 100 internship hospitals across the country by the South Korean Ministry of Welfare showed that as of 11 a.m. on the 8th, a total of 11994 interns and residents were absent, accounting for 929% of the total.

　　With the development of society and the improvement of people’s living conditions, air conditioning has become a necessity in people’s lives. But you know what? The placement of air conditioners is also said to be feng shui. The improper placement of air conditioners will actually block the wealth of the family. So how to place the air conditioner? What are the precautions for air conditioning placement? Let’s take a look.This is due to commercial ac unit Its value attribute is relatively large, and it is easy to become the backbone of the industry. https://puremind.com/product-category/puremind-air-conditioner/commercial-air-conditioner/

　　

　　Air conditioning is a typical product of modern houses, and there is no introduction about air conditioning in any ancient geomantic books. However, air conditioning has obvious influence on the geomantic omen of Yangzhai because of its function of air supply and temperature regulation. So, are there some feng shui precautions for air conditioning, a household appliance that only appeared in modern houses? Let’s sum up some questions about air conditioning feng shui.

　　

　　1. The air outlet of the air conditioner should not face the door.

　　

　　It has been mentioned many times that “storing wind and gathering gas” is the basic principle of Feng Shui. One of the major characteristics of air conditioners is that they can spray air to adjust the indoor temperature. These spouted air currents themselves cause direct disturbance to the gas field of the house. The gas field is too strong, and the air flow and the air flow entering the gate will have an impact, which will directly destroy the stability of the gas field of the house. Not to mention gathering wealth, the popularity will be washed away by the gas field of the house.

　　

　　2. Don’t hang the air conditioner on the sofa or bedside.

　　

　　The wall-mounted air conditioner itself is particularly similar to the beam in shape. As we all know, there can’t be a cross beam above the sofa or bedside, otherwise there will be a problem of the cross beam topping. In fact, air conditioners should also avoid the situation of topping. Moreover, the air conditioner itself has cold air injection, which goes straight to the head or body, and the impact is more direct. Therefore, remind everyone that when choosing the hanging position of air conditioner, try to avoid pressing against people’s body parts.

　　

　　Don’t blow the air conditioner directly on people.

　　

　　In the first article, we emphasize that air conditioning can’t blow on people’s heads, which is mainly from the perspective of air conditioning topping. In fact, even other parts of the body, try not to be blown directly by the air conditioner. Although the air conditioner is cool, it is very easy to catch a cold, stroke or backache, which directly affects people’s health. You can manually change the air outlet direction of the air conditioner to avoid being directly blown.

　　

　　4. Air conditioner should not blow the dining table directly.

　　

　　Experienced friends know that long-term use of air conditioners will absorb a lot of dust and germs. Therefore, for air conditioners that are often used, if the filter screen cannot be cleaned on time, it will also cause the accumulation of foul air in the house. If the air conditioner blows air directly on the dining table, these foul gases and germs can easily be directly adsorbed on our food, which will have an unnecessary impact on our health.

　　

　　5. Don’t blow the air conditioner directly.

　　

　　Some friends will install air conditioning in the kitchen because of the large space in the kitchen. But when installing air conditioning in the kitchen, don’t put the air conditioner directly on the stove mouth, especially on the flame. The reason is very simple. This kind of direct gas field disturbance will not only make the flame unstable and cause safety hazards, but also symbolize the hostess in the image. The direct air conditioning will also have unnecessary effects on the hostess’s own body. So remind everyone, if you have to install air conditioning in the kitchen, don’t let the air conditioning mouth directly face the stove mouth.

　　

　　Location of air conditioner

　　

　　Fans must not be placed in the financial position.

　　

　　If the air conditioner happens to be in the financial position, it will blow away your fortune. The financial position pays attention to hiding the wind and gathering gas, and should be quiet and not moving. They are also fast-running appliances, so they will transfer the airflow from the outside to the home, and plants, fish and the like should be used to stimulate the financial position. Fans can only blow away wealth, which is very unfavorable to home wealth and will soon appear. Therefore, we must pay attention to the fact that the fan must not be placed in the financial position.

　　

　　The fan must not be placed in a fierce position.

　　

　　But the fan is a dynamic substance, which is basically a product of making brake gas. Especially when it is placed in a fierce position, it will provoke fierceness, which is really bad.

　　

　　The cold air that doesn’t start is not enough for feng shui effect.

　　

　　Air-conditioning emits cold and frozen gas, so it belongs to gold in the five elements, which is the same as refrigerator. If the summer is long and the opening time is more than half a year or more, air conditioning will have a great influence on home feng shui, but it should be noted that the air conditioning that is not started is basically not enough to achieve feng shui effect.

　　

　　They belong to gold, and the way to find out where to put them is very simple. Whoever wants gold from a family member, putting air conditioning in the position where the member belongs is the most favorable feng shui decoration. If the father wants gold, put it in the northwest, if the mother wants gold, put it in the southwest. The wind released by the air conditioner will create a geomantic magnetic field. Adjusting the tuyere to the upper side is more beneficial to home feng shui, because in the wind direction, it represents the airflow swirling down from the ceiling and the airflow blowing, which is the best form.

　　

　　Its decoration should be based on the needs of the five elements of family members, and can also be used in conjunction with the lucky time of the year. Find out the bad side and the financial side. If the air conditioner is located in the bad side, the air conditioner on this side should be turned on as little as possible, and feng shui objects should be placed to release two black and five yellow.

　　

　　kitchen

　　

　　The kitchen stove is where the whole family can fill their stomachs. If the air conditioner is directly on the stove fire, it will make the stove fire weak, which will damage the energy of the food in cooking, thus affecting the health of the housing people. In addition, the stove fire is also representative, so it has a great impact on the life of couples.

　　

　　Correction method

　　

　　Don’t install air conditioner if you can, but if you must, blow the wind towards the ceiling or sideways as much as possible.

　　

　　dining room

　　

　　When air conditioners are used for a period of time, dust will inevitably accumulate. Therefore, if the air conditioners in the dining room blow directly on the dining table, it is very likely that the dust will fall into the hot food with the wind, and of course, it is easier to cool the delicious meals on the table. Therefore, it is best not to place the air conditioners in the dining room above or near the dining table.

　　

　　bedroom

　　

　　When people sleep, the sweat pores are wide open and the respiratory system is relatively unguarded. Therefore, if the air conditioner blows directly, it will not only make people feel unwell and catch a cold, but also attract evil spirits more easily.

　　

　　Correction method

　　

　　Raise the air outlet upward, or slightly open the window in the room to evenly blow the cold air.

　　

　　study

　　

　　Air conditioning makes people cool, so it has the function of condensing thinking and improving reading concentration. If we can move the air conditioner in the study to the north and use the energy of air conditioning operation, it will drive Wenchang to good luck, which will certainly benefit candidates or people who study knowledge. Of course, remember not to blow the air outlet toward your face or head, lest your head be unbearable before you finish reading the book.

　　

　　sitting room

　　

　　Air-conditioning is a fast-running electrical appliance, so it will turn the outside air flow into the home, and the southwest of the Year of the Monkey will treat diseases. Therefore, if the air-conditioning at home is placed in this position, it will definitely make the family suffer from illness and illness this year.

　　

　　Correction method

　　

　　Use a small fan to change the wind direction opposite the air conditioner. In addition, in the Year of the Dog, peach blossoms dominate the northeast, Wenchang dominates the west, and the northwest dominates the financial position. If you want to strengthen the above fortune, you can also move the air conditioner to this position, which has a strong effect on luck and transshipment.

　　

　　Popularization of feng shui knowledge of air conditioning

　　

　　Nowadays, people’s living conditions are improving day by day, and the popularization of air conditioning has extended to every household. Air conditioning is warm in winter and cool in summer, which not only improves people’s quality of life, but also brings more warmth and comfort to people. Then, from the perspective of geomantic omen, how to make the layout of air conditioners more in line with the principles of geomantic omen, so as to prosper in people’s career, wealth, marriage and health, and improve people’s quality of life?

　　

　　First, the current three types of home air conditioning

　　

　　At present, home air conditioners can be generally divided into wall-mounted air conditioners, cabinet air conditioners and central air conditioners. According to the principles of geomantic omen that “there is evil spirit when visible” and “there is an image that should respond”, it is considered that there are obvious differences between the “existing form” and “supply cooling and heating mode” of these three types of air conditioners in home, so their functions and functions in home geomantic omen will be different. That is to say, different types of home air conditioning layout in the same location may have different feng shui consequences.

　　

　　Second, the interpretation of three key locations of home air conditioning layout

　　

　　1. Is air conditioning suitable for financial position?

　　

　　It is believed that, first of all, cabinet air conditioners are not suitable for financial position. As we know, financial position is the place where the breath in the home gathers, and cabinet air conditioners will occupy the financial position because of its tall body, and then “squeeze” the wealth; Secondly, central air-conditioning is not suitable for the financial position. Generally speaking, the wind of central air-conditioning blows vertically downward, while the financial position in geomantic omen is generally quiet and motionless. If central air-conditioning is installed above the financial position, its airflow will blow straight down, and the financial position will be exhausted, which is actually an image of money not gathering; Finally, it is considered that the wall-mounted air conditioner is very suitable for the financial position, because it just overcomes the shortcomings of the cabinet air conditioner, which is too large and the air flow in the central space is straight down. Moreover, the wall-mounted air conditioner also has the advantages of high and basic lateral air exhaust. Although it is in the financial position, its air flow is discharged straight ahead, so that while strengthening the air flow in the house, it also maintains the relatively stable and gentle replacement of the air in the financial position, and then uses the air in the financial position to keep fresh.

　　

　　2. Is the air conditioner suitable for Wenchang?

　　

　　It is believed that, generally speaking, all three types of home air conditioners are suitable for layout in Wenchang. Because Wenchang represents school, career, official transport, fame, reputation and influence in geomantic numerology, the layout of home air conditioners in Wenchang will definitely enhance the corresponding energy, and then play the role of prosperity. Then, why can the layout of home air conditioning improve the corresponding energy in Wenchang? Because Wenchang’s general five elements attribute is fire, which is often said to be the main fire. The bright wood fire is the most prosperous image in geomantic numerology, while the five elements of air conditioning discharged from air conditioning are aquatic wood, and the five elements of heating discharged are wood fire, while heating is generally used in winter, and water is also used in winter. Therefore, this forms the image of aquatic wood and wood fire, and its breath gathers in fire, which means Wen and Wenchang; Even more, because of the existence of water, the situation of fire flourishing and wood burning will never be formed, which is also the principle of the five elements of “one (water) four (wood) and the palace master Wang Wen” in Xuankong Feng Shui.

　　

　　3. Is the air conditioner suitable for layout at Taiji point?

　　

　　Taiji point is the center of gravity and center point in the home. It is considered that among the three types of home air conditioners, the central air conditioner is the most suitable layout in Taiji. The central air conditioning is arranged at Taiji point. In the cold winter, warm air comes from the sky, which makes the whole home full of warmth. In the hot summer, the cold wind falls from the “sky”, making the whole home full of sweetness and coolness. As we know, geomantic omen pays attention to the word “image”, and this image is the image of enjoying the grace of heaven and meeting your career. However, wall-mounted air conditioners and cabinet air conditioners are difficult to “hide” and are limited by installation conditions, drainage conditions and other factors, so it is really difficult to achieve the feng shui effect of central air conditioners.

　　

　　Third, the basic feng shui knowledge of home air conditioning layout

　　

　　Warm reminder

　　

　　In the layout of home air-conditioning, the direction of its air outlet is particularly important. Generally speaking, the air outlet of home air-conditioning should not face the places where people are active frequently, mainly the “three places” such as seats, beds and stoves. This is the problem of different effects produced by “actively receiving feng shui energy” and “passively receiving feng shui energy” in the geomantic omen of the Ark. That is to say, when the air outlet of the air conditioner is facing the “three places”, people can only passively receive the feng shui energy, and when the feng shui energy exceeds a “degree” that people can bear, it will naturally do harm to people; However, when the air-conditioning geomantic omen is not directly opposite to the “three positions”, people can fully play their active role by actively receiving the geomantic omen energy, and generally there will be no harm caused by receiving the geomantic omen energy too much.

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According to a report by DPA on May 15, Slovakia Prime Minister Robert Fizo was seriously injured in an attempted assassination on the 15th. After several hours of surgery, he has regained consciousness.

Reports by Slovakia TA3 TV and Independent Daily on the evening of the 15th did not provide further information on Fizo’s health.

According to official news released on the evening of the 15th, 59-year-old Fizo’s life is in danger.

Reports mentioned that Fizo was shot by a 71-year-old man in the country’s mining town of Handlowa. According to witnesses, the man shot Fizo several times as he greeted supporters after a cabinet meeting.

According to the government, the shooting was politically motivated. Media reports said that the gunman’s wife was also interrogated by the police.

According to a Reuters report on May 15, the gunman who attacked Slovakia Prime Minister Fizo fired five shots in a row, putting him in critical condition and undergoing several hours of surgery.

Slovakia Deputy Prime Minister and Minister of the Environment Tomashtaraba told reporters: Fortunately, the operation went smoothly. I think he will survive in the end and is now out of danger.

Taraba also revealed that one bullet penetrated Fizo’s abdomen and another hit a joint.

Slovakia Media A quoted unnamed source as saying that Fizo’s surgery has ended and is currently in stable condition. (Compiled by Guo Jun)

　　Central air conditioning is an indispensable energy consumption operation system in modern buildings. Central air conditioning system not only provides people with comfortable living and working environment, but also consumes a lot of energy. According to statistics, the energy consumption of buildings in China accounts for about 30% of the total energy consumption. In buildings with central air conditioning, the energy consumption of central air conditioning accounts for about 70% of the total energy consumption, and it is increasing year by year. Therefore, how to efficiently use the energy and energy saving of central air conditioning system has become an urgent problem to be solved.from Puremind Split Air Conditioners Looking at the development prospects, the future will always bring positive effects. https://puremind.com/puremind-hot-sale/

　　

　　The normal operation of the central air conditioning system, its energy consumption mainly has two aspects [1″ target=_blank>: on the one hand, it is the energy consumption of cold and heat sources to supply air handling equipment with cold and heat; On the other hand, in order to transport air and water, fans and pumps need energy to overcome the flow resistance. The energy consumption of central air conditioning system is affected by many factors, and many operation links have energy-saving measures. Therefore, energy-saving of central air conditioning is a comprehensive project. The following introduces several commonly used energy-saving measures in terms of energy consumption of cold and heat sources and power consumption.

　　

　　1. Energy-saving measures for cold and heat sources

　　

　　1.1 Temperature and humidity control

　　

　　From the air treatment process of central air conditioning system, it can be seen that the lower the indoor temperature and relative humidity in summer, the greater the energy consumption of system equipment; The higher the indoor temperature and relative humidity in winter, the greater the energy consumption of the system equipment, and the corresponding initial investment and operating costs also increase.

　　

　　Because everyone’s requirements for comfort are very different, there can be a wider comfort zone for civil central air conditioning. In this comfort zone, when cooling in summer, take a higher temperature and humidity value; When heating in winter, a certain energy-saving effect can be obtained by taking a lower temperature and humidity value. The change of temperature and humidity in the building is closely related to building energy saving. According to empirical statistics, if the set temperature is lowered by 1≧ in summer, the energy consumption will increase by 9%. If the set temperature is raised by 1≧ in winter, the energy consumption will increase by 12%. Therefore, it is an effective measure to control the temperature and humidity in the building within the precision range of the set value.

　　

　　In order to reduce energy consumption, the indoor temperature and humidity base of air-conditioned rooms should be raised as much as possible in summer and lowered as much as possible in winter under the condition of meeting production needs and human health. At present, some owners blindly pursue the realm of “cold enough” and greatly improve the design standard of indoor temperature and humidity, which not only wastes a lot of energy unnecessarily, but also produces the negative effect of comfort.

　　

　　The higher the temperature and humidity control precision of air conditioning system, the better the comfort and the more obvious the energy-saving effect. The accuracy of the signal measured by the front end of the air conditioning system directly affects the precise control degree of the central air conditioning system. Therefore, the measured signals, especially analog signals such as temperature and humidity, must be as accurate as possible.

　　

　　Also, BAS with high control accuracy must be selected to control the central air conditioner. Because BAS uses DDC (Direct Digital Controller) to directly control the opening of electric water valve without intermediate regulator; In addition, DDC contains a wealth of calculation and control software, such as PID algorithm, fuzzy control algorithm, genetic algorithm and so on, to ensure the control accuracy.

　　

　　1.2 cold source efficiency control

　　

　　The performance index to evaluate the refrigeration efficiency of cold source is COP (Coefficient Of Performance). Refrigeration coefficient refers to the amount of cold energy that can be obtained per unit power consumption. The refrigeration coefficient has nothing to do with the nature of refrigerant, but only depends on the temperature T0 of the cooled object and the coolant temperature Tk. The higher T0, the lower Tk and the higher the refrigeration coefficient. So don’t make the chilled water temperature too low and the cooling water temperature too high during the actual operation of the air conditioning system, otherwise the refrigeration coefficient will be low, which will consume a lot of work and high power consumption to produce unit cooling capacity, and increase the energy consumption of the building. The following measures can be taken to improve the efficiency of cold source:

　　

　　1) reduce the cooling water temperature

　　

　　The lower the cooling water temperature, the higher the refrigeration coefficient of the cooler. For every 1≧ increase in the supply temperature of cooling water, the COP of the chiller decreases by nearly 4%. To reduce the temperature of cooling water, it is necessary to strengthen the operation management of cooling tower. First of all, for the cooling tower that stops running, the valves in and out of the water pipes should be closed. Otherwise, because the water temperature from the stopped cooling tower is high, the temperature of the mixed cooling water will increase and the refrigeration coefficient of the cooler will decrease. Secondly, after the cooling tower is used for a period of time, it should be overhauled in time, otherwise the efficiency of the cooling tower will decrease and the cooling water cannot be fully cooled.

　　

　　2) increase the temperature of chilled water.

　　

　　The higher the temperature of chilled water, the higher the refrigeration efficiency of the chiller. When the temperature of chilled water supply is increased by 1≧, the refrigeration coefficient of the chiller can be increased by 3%, so don’t blindly reduce the temperature of chilled water in daily operation. First of all, don’t set the set temperature of chilled water of the cold machine too low. Secondly, the water valve of the stopped chiller must be closed to prevent some chilled water from taking the bypass pipeline, otherwise, the amount of water passing through the running chiller will be reduced, resulting in the temperature of chilled water being lowered to a too low level by the chiller.

　　

　　2. Energy-saving measures for power consumption

　　

　　2.1 Transportation energy consumption control

　　

　　Power consumption mainly refers to the electric energy consumed by fans and pumps in system operation. Calculation formula of input power from fan and water pump:

　　

　　(1) (W): input power; : volume flow; : indenter; Eta: efficiency

　　

　　From Formula (1), it can be seen that reducing power consumption can be considered from the following three aspects: reducing flow, reducing system resistance and improving the efficiency of fans and pumps. The following measures can be adopted in engineering practice:

　　

　　1) adopt large temperature difference.

　　

　　If the temperature difference between the supply and return water (or the return air) used to transport cold and hot water (or air) in the system is large, then when the ratio between it and the original temperature difference is m, it is known from the flow calculation formula that the flow rate is reduced to 1/m3 when the large temperature difference is used. At this time, the power required by the water pump or fan will be reduced to 1/m3. It can be seen that the energy-saving effect of increasing the temperature difference is obvious.

　　

　　On the premise of meeting the requirements of central air conditioning accuracy, personnel comfort and technology, the temperature difference of air supply should be increased as much as possible. It should be noted that the temperature difference between supply and return water should not be greater than 8≧.

　　

　　2) choose low flow rate.

　　

　　Because the power consumption required by pumps and fans is roughly proportional to the flow velocity in the pipeline system, in order to achieve energy-saving operation effect, high flow velocity should not be adopted in design and operation. In addition, the low flow rate in the main pipe is also beneficial to the stability of the hydraulic condition of the system. For example, changing the rotational speed of the fan can change the performance parameters of the fan. The power of the fan has a cubic relationship with the rotational speed, while the flow rate has a linear relationship with the rotational speed. Lowering the rotational speed can greatly reduce the energy consumption while reducing the flow rate. When the flow rate is reduced by 1/3, the energy consumption can be reduced by about 70.4%, and when the flow rate is reduced by 1/2, the energy consumption can be reduced by about 87.5%, and the efficiency of the fan is basically unchanged, and it can still work stably and efficiently.

　　

　　3) adopt energy-carrying medium with high conveying efficiency.

　　

　　Under normal circumstances, the energy consumption of transporting cold and heat energy with water is less than that with air, and the diameter of water pipes used to transport the same cold and heat energy is much smaller than that of air pipes, which occupies a much smaller building space. This is also one of the main reasons for the rapid development of central air conditioning in recent years.

　　

　　Therefore, for the centralized refrigeration mode, in principle, the chilled water prepared by the equipment in the computer room should be transported as far as possible to the vicinity or use point of each central air-conditioning partition, and the air should be treated by the terminal non-independent central air-conditioning units (such as cabinet air-conditioning units and fan coils) for local use or for use in nearby rooms.

　　

　　2.2 VAV system control

　　

　　VAV system is an energy-saving countermeasure against the shortcomings of power consumption in air supply system. VAV system can be divided into two types: one is AHU！VAV system of air conditioner; One is the indoor fan variable air volume system (FCU-VAV system) in FCU system. AHU-VAV system is to fix the air supply temperature in the whole air duct system and adjust the air supply volume of the blower to cope with the change of indoor air conditioning load. In FCU-VAV system, the cold water supply is fixed, and the indoor FCU is equipped with a stepless power controller to change the air supply, that is, to change the heat exchange rate of FCU to adjust the indoor load change. These two methods can reduce the power consumption of the blower by adjusting the air volume, and at the same time, they can also increase the operating efficiency of the heat source machine and save the power consumption of the heat source, so they can achieve energy-saving effects in both air supply and heat source.

　　

　　The cooling capacity sent into the room can be determined by the following formula:

　　

　　2

　　

　　Where: c is the specific heat capacity of air, kj/(kg≧); ρ is the air density, Kg/m3; L is the air supply volume, m3/S; Tn is the indoor temperature,≧; Ts is the supply air temperature,≧; Q is the heat absorbed (or put) into the room, KW.

　　

　　If the air supply temperature is set as a constant and the air supply volume L is changed, different Q values can be obtained to keep the room temperature unchanged. Variable air volume control can adopt an air supply device that automatically adjusts the air supply volume according to the change of indoor load. When the indoor load decreases, it can keep the air supply parameters unchanged (no need to reheat) and keep the indoor temperature stable by automatically reducing the air volume. In this way, it can not only save the reheat required by the constant air volume system to increase the air supply temperature, but also reduce the power consumption of the fan and the cooling capacity of the refrigerator due to the reduction of the treated air volume. According to various data, VAV can save energy by 30% ~ 50% compared with constant air volume.

　　

　　2.3 Frequency conversion control

　　

　　In most buildings, the central air conditioning is at the maximum load only for a few days in a year. The cooling load of central air conditioning is always changing dynamically, such as the changes of various factors such as morning and evening, climate, passenger flow and activity content, which affect the cooling load of central air conditioning in real time. Generally, the cooling load fluctuates in the range of 5 ~ 60%, and most buildings are at least 70% in this situation every year. However, most central air conditioners are driven by maximum cooling load and maximum power due to system design. In this way, the contradiction between the actual cooling load and the maximum power output is caused, resulting in a huge waste of energy. This contradiction can be solved by adopting frequency conversion control.

　　

　　1) Fan and water pump frequency conversion control

　　

　　In the past, the AC motor itself didn’t adjust the speed, so the central air conditioning system had to rely on baffles and valves to adjust the air and water flow, and a lot of electric energy was wasted on baffles and valves. If the fan water pump is regulated by frequency conversion, the energy wasted on baffles and valves will be saved, and the average energy saving effect of each pump will be considerable.

　　

　　For the fan water pump, according to the principle of fluid mechanics, the parameters under similar working conditions have the following relationship [2″ target=_blank>:

　　

　　3

　　

　　Where Q1, H1, n1 and N1 are the flow, lift, power and rotation speed before the rotation speed change, respectively;

　　

　　Q2, H2, n2, N2: the flow, lift, power, and rotation speed after the rotation speed is changed respectively.

　　

　　According to Formula (3), the flow rate is proportional to the rotational speed, the pressure is proportional to the square of the rotational speed, and the power consumed is proportional to the cubic power of the rotational speed. For variable frequency speed regulation, the speed n is basically proportional to the power frequency f, when the power frequency f decreases, the motor speed also decreases, and the required power decreases rapidly with the cubic power of the speed, which shows that the energy-saving effect is very remarkable. Take the fan as an example, if the required air volume is 80% of the rated air volume, the speed will also drop to 80% of the rated speed, and the shaft power will drop by 51.2%; When the required air volume is 50% of the rated air volume, the shaft power drops by 12.5%. This power saving effect is also very impressive. It has been proved that the frequency conversion control of fans and pumps can save energy by 40% ~ 50%.

　　

　　2) Frequency conversion control of water chillers

　　

　　Because the compressor does not rule out the possibility of long-term operation under full load, the capacity of the motor can only be determined according to the maximum demand, so the design margin is generally large. In actual operation, the proportion of light load operation time is very high. Frequency conversion control is adopted to adjust the speed of compressor, so as to control the refrigeration capacity and keep the refrigeration unit in the best (most reasonable) operation state. Frequency conversion control improves the efficiency of air conditioner and the operation effect of refrigeration unit, thus realizing energy saving.

　　

　　The principle of variable frequency compressor is to adjust the displacement of compressor per unit time by adjusting the speed of compressor, so as to achieve the purpose of adjusting the refrigeration capacity. The mathematical relationship between refrigeration capacity and compressor frequency is as follows:

　　

　　4

　　

　　Where n is the rotational speed, f is the frequency of the motor, p is the polar logarithm of the motor, s is the slip of the motor, λ is the leakage coefficient, Ps is the suction pressure, vh is the suction volume, ni is the polytropic index, εi is the pressure ratio (exhaust/suction), δ0 is the relative pressure loss coefficient, and Zs and Zd are the actual gas compressibility coefficients, which are the average energy efficiency ratio.

　　

　　According to Formula (4), the refrigeration capacity is directly proportional to the frequency, so the refrigeration capacity can be controlled by frequency conversion regulation, thus achieving the energy-saving effect.

　　

　　Some adjustment methods (such as adjusting the valve opening and changing the blade angle) can not reduce the operating efficiency of the motor even if the demand is small. After adopting frequency conversion speed regulation, when the demand is small, the speed of motor can be reduced and the running power of motor can be reduced, thus further realizing energy saving. It has been proved that the frequency conversion control of water chillers can save energy by 20% ~ 30%.

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According to a BBC report on the 20th, researchers at the University of Amsterdam in the Netherlands said at a medical conference held on the 18th that they successfully removed the HIV virus (HIV) from infected cells using CRISPR gene editing technology.

Screenshots of related reports

It is reported that although existing drugs can prevent the HIV virus from further penetrating into the human body, they cannot clear the existing virus in the patient’s body. Even if patients receive effective treatment and the HIV virus in their bodies enters a dormant or latent state, they still carry HIV DNA or genetic material.

According to the BBC, the CRISPR gene editing technology used by the researchers is similar in principle to scissors, which can remove or inactivate HIV-infected cells by cutting DNA. This gene editing technology won the 2020 Nobel Prize in Chemistry.

At present, the scientific research process at the University of Amsterdam is still in the proof-of-concept stage, and it will take a long time for it to be truly applied to AIDS treatment.

Scientists believe that if this new technology can be further developed, it will be expected to eliminate all HIV in the human body, thereby curing AIDS. However, some virologists also said that the possible off-target effects and long-term side effects of this technology are worrying.

Wen| Reporter Leng Shuang

　　There are many kinds of refrigeration methods, such as gas expansion refrigeration, liquid gasification refrigeration, vortex tube refrigeration and thermoelectric refrigeration. Among them, liquid gasification refrigeration is the most widely used, and its working principle is to realize refrigeration by using the heat absorption of liquid gasification.At first, chilled water system It developed out of control and gradually opened up a sky of its own. https://puremind.com/product-category/puremind-air-conditioner/industrial-chiller/

　　

　　1, the working principle of air conditioning (mainly refrigeration, heating on the contrary):

　　

　　The high-temperature and high-pressure refrigerant discharged from the compressor flows through the outdoor heat exchanger through the four-way valve, and dissipates heat to the outdoor air through heating transfer, and the refrigerant changes from gaseous state to liquid state-throttles and depressurizes through capillary (or solenoid valve)-one-way valve-filter-two-way valve (outdoor high-pressure pipe)-enters the indoor heat exchanger to absorb heat (realize refrigeration)-outdoor three-way valve (outdoor low-pressure pipe). Complete a single-loop refrigeration cycle.

　　

　　2. Types of components in refrigeration system:

　　

　　The air conditioning refrigeration system is mainly composed of four parts and some auxiliary equipment in the refrigeration system.

　　

　　The four major pieces are:

　　

　　compressor

　　

　　condenser

　　

　　Throttle mechanism

　　

　　Evaporator composition.

　　

　　Auxiliary equipment:

　　

　　Oil separator;

　　

　　Drying filter;

　　

　　Liquid storage tank;

　　

　　Electromagnetic four-way reversing valve;

　　

　　Solenoid valve; Check valve

　　

　　3, the working principle of each component

　　

　　Compressor: As the “heart” of refrigeration system, it has an important influence on the performance, noise, energy consumption, vibration and service life of air conditioning. According to the principle of thermodynamics, it can be divided into volumetric type and velocity type.

　　

　　Volumetric type: a certain volume of gas is sucked into the cylinder and the internal volume of the cylinder is changed to realize gas compression and forced discharge.

　　

　　Speed type: make the inhaled gas get a certain speed, and then slow down, so that kinetic energy can be converted into pressure energy and then discharged. The growth of gas is converted from speed.

　　

　　one

　　

　　Scroll compressor: It is formed by meshing two vortexes of stator and rotor.

　　

　　Rotor compressor: it consists of spindle with eccentric wheel, cylinder, sleeve, air inlet, slide plate, spring, exhaust valve and exhaust port.

　　

　　Condenser: The condenser transfers the refrigerating capacity of the evaporator in the refrigeration system to the environmental medium (cooling water or air) together with the power consumption of the compressor. According to cooling, it can be divided into air-cooled type, water-cooled type and evaporative type. When cooling, it mainly radiates heat to the outside, and when heating, it absorbs heat to the outside.

　　

　　Evaporator: The main function of the evaporator is to boil and evaporate the low-temperature and low-pressure refrigerant liquid that has entered the throttle in the evaporator, absorb the heat of the cooled medium, and then become low-pressure saturated (usually overheated) vapor itself, which is continuously sucked away by the compressor. In other words, the evaporator is a heat exchange device that absorbs heat (that is, outputs cold energy).

　　

　　Throttle element: Throttle element is one of the four main elements in the refrigeration system. Its main function is to throttle and reduce the pressure of high-pressure liquid refrigerant, ensure the pressure difference between condenser and evaporator, and make the refrigerant entering the evaporator absorb heat and evaporate at the required low pressure, thus achieving the purpose of refrigeration and cooling. Adjust the refrigerant flow into the evaporator to adapt to the load change of the evaporator and make the system run normally.

　　

　　Capillary: It is a very thin tube, usually with an inner diameter of 0.5 ~ 2.5 mm and a length of 1 ~ 5 m.. When the refrigerant flows in the tube, it is necessary to overcome the resistance in the tube, which naturally produces a certain pressure drop.

　　

　　Capillary characteristics: Because it is in the normally open state, when the compressor stops, the high and low pressure can be quickly balanced, which is conducive to the compressor starting again. Simple structure, convenient manufacture and low price. For the heat pump system, there is no import and export problem in the throttling process of refrigerant in capillary [this article source: refrigeration encyclopedia WeChat official account” target=_blank>. Using capillary refrigeration system, the performance of the unit is very sensitive to the refrigerant charge. When the operating conditions of the refrigeration system change, the capillary tube has poor ability to adjust the refrigerant flow. Due to the small inner diameter of capillary and long pipeline, it is easy to be blocked, so attention should be paid to the drying and cleaning of the system. Generally, a dry filter is set in front of the capillary to prevent clogging.

　　

　　Thermal expansion valve: the regulating valve that controls the liquid supply of evaporator, and it is also the throttle valve of refrigeration device. Thermal expansion valve uses the change of superheat of refrigerant at evaporator outlet to adjust the flow. According to different structures, it can be divided into internal balance type and external balance type.

　　

　　Disadvantages of thermal expansion valve: low control precision and limited adjustment range. The diaphragm deformation of valve body is limited, which makes the change range of valve needle opening smaller, so the adjustment range of flow is small. When large flow regulation is required, it cannot be met. The high-temperature gas at the place where the signal feedback has a lag evaporator must first heat the shell of the temperature sensor, which has a large thermal inertia, leading to the lag of the reaction.

　　

　　2

　　

　　Electronic expansion valve: the application of electronic expansion valve overcomes the shortcomings of thermal expansion valve and provides conditions for the intelligence of refrigeration device. The electric signal generated by adjusting parameters is mainly used to control the voltage or current applied to the expansion valve, so as to achieve the purpose of adjustment, so that the control system of the electronic expansion valve is complicated and the price is high.

　　

　　Electronic expansion valve classification:

　　

　　Electromagnetic electronic expansion valve;

　　

　　Electric electronic expansion valve.

　　

　　4. Auxiliary equipment of refrigeration system

　　

　　Oil separator: The high-pressure gas (gaseous working medium and lubricating oil) from the compressor enters the oil separator to separate the lubricating oil from the working medium gas and flows down along the inner wall of the cylinder. The working gas is led out of the oil separator from the central pipe through the porous baffle. The separated lubricating oil is concentrated in the lower part of the oil separator and can be discharged regularly, or the lubricating oil can be automatically returned to the crankcase of the compressor by using the ball valve.

　　

　　Drying filter: The function of drying filter is to absorb moisture in refrigeration system, prevent impurities in the system from passing through, and prevent the pipeline of refrigeration system from being blocked by ice and dirt. Because the most easily blocked part of the system is the capillary (or expansion valve), the drying filter is usually installed between the condenser and the capillary (or expansion valve).

　　

　　Liquid storage tank: During the operation of the refrigeration system, the circulating amount of refrigerant in the system will change due to the change of working conditions or the adjustment of refrigeration capacity. Setting the liquid storage tank can balance and stabilize the refrigerant circulation in the system by using the liquid storage capacity of the liquid storage tank, so that the refrigeration system can be in normal operation. In addition, when a component in the refrigeration system fails and needs to be dismantled and repaired, the system refrigerant can be recovered to the liquid storage tank through certain operation methods.

　　

　　The liquid storage tank is generally arranged between the condenser and the throttling element, so that the refrigerant liquid in the condenser can smoothly enter the liquid storage tank. The position of the liquid storage tank should be lower than that of the condenser.

　　

　　Electromagnetic four-way reversing valve: after the electromagnetic coil is energized, it changes the action direction of the valve block in the valve body and changes the flow direction of the refrigerant. So as to achieve the purpose of cooling or heating.

　　

　　three

　　

　　Solenoid valve: Solenoid valve is usually installed in front of the expansion valve to directly control the amount of refrigerant entering the evaporator. It can also be installed before the compressor unloading cylinder to control the unloading of the compressor cylinder.

　　

　　There are two kinds:

　　

　　Direct opening and closing solenoid valve;

　　

　　Indirect solenoid valve.

　　

　　One-way valve: The one-way valve is usually connected in parallel with the auxiliary capillary, and the two are connected in series with the main capillary. One-way valve is a tubular element with a movable spherical or hemispherical plug made of stainless steel or nylon. Combined with capillary tube, it can adapt to two different operating conditions of refrigeration and heating.

　　

　　5. Types and States of Refrigerant

　　

　　Air conditioning refrigerants mainly include R22, R410A and R32.

　　

　　R22 is a medium-temperature refrigerant, with the standard of -40.8 degrees, the solubility of water in R22 is very small, and it is mutually soluble with mineral oil, and R22 does not burn or explode, with little toxicity and strong permeability.

　　

　　R410A is a HFC refrigerant which is composed of R32 and R125 by 50% and 50% by mass. [This article comes from WeChat official account, a refrigeration encyclopedia” target=_blank>, which belongs to a near azeotrope, and its thermodynamic properties are very close to that of a single refrigerant. Compared with R22, R410A’s condensation pressure is increased by 1.6 times, and it is a high-pressure refrigerant, so it is necessary to improve the compression strength of the system.

　　

　　R32 is the abbreviation of difluoromethane, which is a kind of coolant with zero ozone loss potential. It is a gas at room temperature and a colorless and transparent liquid under its own pressure. It is soluble in oil and insoluble in water, and it is an energy-saving and carbon-reducing environment-friendly non-toxic refrigerant, but it is flammable and explosive!

　　

　　6. Refrigerant status

　　

　　Saturated refrigerant: Vapor-liquid conversion in saturated refrigerant is in transport equilibrium, and liquid and gas at this time are in saturation.

　　

　　There is a one-to-one correspondence between saturation temperature and saturation pressure, and the saturation pressure increases with the increase of saturation temperature, and one of them will change and the other will change accordingly. In the system, the refrigerant in the evaporator absorbs heat and the refrigerant in the condenser releases heat, where the refrigerant is saturated.

　　

　　Superheat: Under a certain pressure, the temperature of superheated steam exceeds the saturation temperature.

　　

　　Overheating: the temperature of refrigerant vapor in superheated refrigerant is higher than the saturation temperature under the corresponding saturation pressure, and the liquid refrigerant will overheat after evaporation. In the case of overheating, there is no one-to-one correspondence between the temperature and pressure of refrigerant gas.

　　

　　Near the outlet of the evaporator, the refrigerant continues to absorb heat after complete evaporation and becomes superheated refrigerant with a temperature higher than the saturation temperature. The refrigerant enters the compressor through the suction pipe in case of overheating.

　　

　　Supercooling: The liquid temperature of the supercooled refrigerant is lower than the saturation temperature at the corresponding saturation pressure, and supercooling will only occur when there is no steam in the fluid refrigerant. In the case of supercooling, there is no one-to-one correspondence between the temperature and pressure of refrigerant liquid.

　　

　　Between the outlet of the condenser and the throttle valve, the refrigerant may continue to cool exothermically and become supercooled after condensing into saturated liquid.