How does solar air conditioning achieve cooling?

Basic Working Principle of Solar Absorption Air Conditioning

A solar absorption air conditioning system consists of two main components: a solar collector and an absorption refrigerator. Absorption refrigeration uses a binary solution consisting of two substances as the working medium. These two substances have different boiling points at the same pressure, the component with the high boiling point is called the absorber, and the component with the low boiling point is called the refrigerant. There are two commonly used combinations of absorption refrigerants: one is lithium bromide - water, usually applicable to large central air conditioning; the other is water - ammonia, usually applicable to small air conditioning. Absorption chiller is mainly composed of generator, condenser, evaporator and absorber, as shown in Figure 1. This paper takes lithium bromide absorption chiller as an example. In the refrigerator operation process, when the lithium bromide aqueous solution is heated by the heat medium water in the generator, the water in the solution continues to vaporize; when the water in the condenser enters the evaporator through the throttle valve, it rapidly expands and evaporates, and absorbs a large amount of heat from the refrigerant water in the evaporator in the evaporation process, and in the process, the low-temperature water vapor enters the absorption tower, and is absorbed by the concentrated lithium bromide solution in the absorption tower. The concentration of the solution is gradually reduced and the solution is pumped back to the generator to complete the whole cycle. The so-called solar absorption refrigeration is the use of solar collectors for the absorption chiller to provide the heat medium water required by its generator. The higher the temperature of the heat medium water, the higher the coefficient of performance (COP) of the chiller, and thus the higher the cooling efficiency of the air-conditioning system. For example, if the temperature of the heat medium water is 60℃, then the police refrigerator is 0?40; if the temperature of the water heat storage medium is about 90℃, the police in the refrigerator is 0?70; if the temperature of the water heat storage medium is about 120℃, the police refrigerator can be up to 1?more than 10. The traditional absorption air conditioning system mainly consists of the absorption refrigerator, the air conditioning box (or the fan coil), the boiler and other components, and the solar energy Absorption air-conditioning system is based on the addition of solar collectors, water storage tanks and automatic control systems. Solar absorption air-conditioning system can realize summer cooling, winter heating, year-round domestic hot water and other functions. Its working principle is shown in Figure 2. Cooling and heating power (kW) 100 air conditioning, heating area (m2) 1000 hot water supply 32 (non-air conditioning heating season) (tons / day) collector-type heat pipe vacuum tube lighting area (m2) 540 average daily efficiency (%) 35-40 (air conditioning, 51 (when providing hot water) chiller-type water heater-type single-stage lithium bromide heat medium water temperature 88 refrigerant water temperature (℃) 8 coefficient of performance (COP ) 0.07 In summer, the hot water heated by the collector enters the storage tank first. When the hot water temperature reaches a certain value, the storage tank provides the refrigerant water to the refrigerator; the cooling hot water from the refrigerator returns to the storage tank and is heated by the collector into high temperature hot water. The refrigerant water produced by the refrigerator is led to the air conditioning box for the purpose of refrigeration and air conditioning. When solar energy is not enough to provide high temperature heat medium water, the heat can be supplemented by an auxiliary boiler. In winter, the hot water heated by the collector is put into the storage tank. When the hot water temperature reaches a certain value, the storage tank provides hot water directly to the air-conditioning box for heating and warming purposes. When solar energy cannot meet the requirements, the heat can also be supplemented by the auxiliary boiler. In the non-air conditioning heating season, as long as the hot water collector with the heat exchanger in the storage tank directly heated to life, the cold water in the storage tank can be gradually heated to use

Solar refrigeration refrigeration

According to the different ways of energy conversion, the solar energy-driven refrigeration are mainly the following two ways: one is to achieve photoelectric conversion, and then realize the electric refrigeration; the second is the conversion of photo-thermal, and then Realization of thermal refrigeration. It is the use of photovoltaic conversion device will be converted to solar energy into electrical energy, and then used to drive the semiconductor refrigeration system or conventional compression refrigeration system to realize the cooling method, that is, photovoltaic semiconductor refrigeration and photovoltaic compression refrigeration. The premise of this cooling method is to convert solar energy into electrical energy. The key is the photovoltaic conversion technology, which must use a photovoltaic converter receiver, or photovoltaic cell, which works on the principle of the photovoltaic effect. Solar Thermoelectric Cooling. Solar semiconductor refrigeration is a special refrigeration method that utilizes electrical energy generated by solar cells to supply a semiconductor refrigeration device to achieve heat transfer. The theory of semiconductor refrigeration is based on the thermoelectric effect of solids, i.e., when a direct current passes through a circuit consisting of two different conductive materials, the junction will produce heat absorption or exothermic phenomena. How to improve the performance of the material to find a more ideal material has become an important issue in solar semiconductor refrigeration. Solar semiconductor refrigeration is widely used in national defense, scientific research, medical and health care and other fields, as the cooler of electronic equipment and instruments, or used for low-temperature measuring instruments, instruments, or to make a small thermostat device. At present, the efficiency of solar semiconductor refrigeration devices is still relatively low, COP is generally around 0.2 ~ 0.3, much lower than compression refrigeration. Photoelectric compression refrigeration. Photoelectric compression refrigeration process first use photoelectric conversion device will be converted to solar energy, its refrigeration process for conventional compression refrigeration. The advantage of photoelectric compression refrigeration is the use of mature and efficient compression refrigeration technology can easily obtain the cold. Photoelectric compression refrigeration systems have been used for domestic and pharmaceutical refrigeration in sunny countries and regions such as Africa, where power facilities are scarce. However, their cost is about 3 ~ 4 times that of conventional refrigeration cycles. With the improvement of the efficiency of photovoltaic conversion device and the reduction of cost, photovoltaic solar refrigeration products will have broad prospects for development. Solar thermal conversion refrigeration, first of all, is to convert solar energy into thermal energy, and then use thermal energy as external compensation to achieve the purpose of refrigeration. Photo-thermal conversion to achieve refrigeration mainly from the following directions, namely, solar absorption refrigeration, solar absorption refrigeration, solar dehumidification refrigeration, solar vapour compression refrigeration and solar vapour injection refrigeration. Solar absorption refrigeration has entered the application stage, while solar absorption refrigeration is still in the experimental research stage. Solar absorption refrigeration research. Solar absorption refrigeration research is the closest to reality, the most conventional configuration is:The use of solar collectors to collect solar energy, used to drive a single-effect, double-effect or two-stage absorption refrigerator, the working medium is mainly used lithium bromide - water, when the solar energy is insufficient can be used for fuel oil or coal boiler for auxiliary heating. The main components of the system are basically the same as the ordinary absorption refrigeration system, the only difference is that the generator of the heat source of solar energy rather than a high-temperature heat source of steam, hot water or high-temperature heating generated by the exhaust gas boiler. Solar absorption refrigeration. Solar absorption refrigeration system refrigeration principle is through the adsorption bed in the solid adsorbent on the refrigerant periodic adsorption desorption process to realize the refrigeration cycle. Solar absorption refrigeration system mainly consists of solar absorption collector, condenser, liquid storage, evaporator, valve and so on. Commonly used adsorbents and refrigerant substances are activated carbon - methanol, activated carbon - ammonia, calcium chloride - ammonia, silica gel - water, metal hydride - hydrogen and so on. Solar absorption refrigeration system has the advantages of simple structure, no moving parts, low noise, no need to consider the advantages of corrosion, etc., and its cost and operating costs are relatively low.

Refrigeration principle of solar house

Solar house using absorption refrigeration is reasonable and feasible, the current lithium bromide absorption refrigeration system is more widely used. Absorption refrigeration efficiency is low, the size of the equipment is large, but the advantage is that you can use a low-grade heat source, the hot water produced by solar collectors can be utilized by absorption refrigeration. Although refrigeration efficiency is low, hot water does not require complex and expensive equipment, which means that hot water is cheap, so the overall value of the system remains high. Furthermore, such systems are dual-supply of heat and cold, meaning that the low-temperature hot water from the cooling system can be used for domestic hot water in the room without consuming other energy. Of course, there are also solar room refrigeration using photovoltaic power generation, which in turn drives a conventional compression refrigerator solution, with the advantage of simplicity and compactness, allowing the use of standardized equipment. The disadvantage is that the overall efficiency is still very low, the price of the equipment is too high, in the life cycle of the equipment, even half of the cost is unlikely to be recovered, there is no commercial value.

How does solar air conditioning enable cooling?

At present, countries around the world are stepping up research on solar air conditioning technology. Italy, Spain, Germany, the United States, Japan, South Korea, Singapore and Hong Kong and other countries have been or are building solar air conditioning systems. This is because the energy consumption of air conditioning in developed countries accounts for a large proportion of annual civilian energy consumption, and the use of solar-powered air conditioning systems is of great significance to the conservation of conventional energy and the protection of the natural environment. In order to further broaden the scope of application of solar energy, so that it plays a greater role in energy conservation and environmental protection, China in the "Ninth Five-Year Plan" period of solar air-conditioning technology research, through technological research and systematic demonstration, to solve the technical problems of solar air-conditioning, so as soon as possible to achieve solar air-conditioning commercialization provides the basis for the technology. Solar absorption air-conditioning system mainly consists of two parts: solar collector and absorption refrigerator. Absorption refrigeration is carried out by utilizing a binary solution consisting of two substances as the work mass. These two substances have different boiling points at the same pressure, and the component with a high boiling point is called the absorber and the component with a low boiling point is called the refrigerant. There are two commonly used adsorption refrigerant combinations: one is lithium bromide - water, usually for large central air conditioning; the other is water - ammonia, usually for small air conditioning. Absorption chiller is mainly composed of generator, condenser, evaporator and absorber, as shown in Figure 1. This paper takes lithium bromide absorption chiller as an example. In the refrigerator operation process, when the lithium bromide aqueous solution is heated by the heat medium water in the generator, the water in the solution continues to vaporize; when the water in the condenser enters the evaporator through the throttle valve, it rapidly expands and evaporates, and absorbs a large amount of heat from the refrigerant water in the evaporator in the evaporation process, and in the process, the low-temperature water vapor enters the absorption tower, and is absorbed by the concentrated lithium bromide solution in the absorption tower. The concentration of the solution is gradually reduced and the solution is pumped back to the generator to complete the whole cycle. The so-called solar absorption refrigeration is the use of solar collectors to provide absorption chillers with the heat medium water required by their generators. The higher the temperature of the heat medium water, the higher the coefficient of performance (COP) of the chiller, and thus the higher the cooling efficiency of the air conditioning system. For example, if the temperature of the heat medium water is around 60°C, the COP of a refrigerator is around 0