At present, the occupancy rate of 100 household electric fans in urban areas in China has reached 200%, and the air conditioner possession rate is still less than 10%. The main factors that create such disparity are price and power consumption. As far as the price is concerned, there is a gap of 300-2000 yuan between the electric fan and the single-cooling air-conditioning window machine, and there is no suitable main cooling fan product to fill. To this end, China's patent system in the past 10 years (1985.4-1995.12) is expected to fill the above-mentioned blank non-mainstream chiller patent application search, a total of more than 200 related patent applications. From the cold source point of view, the number is the first of the water evaporation type (a third of the strong), followed by underground cooling type, semiconductor refrigeration type, refrigerator cooling type, low power air conditioning, solar cooling, gas Refrigeration and heat pipe cooling.
The number of applications for water evaporation and cooling is the highest because the water quality of the refrigerant is cheap and easy to obtain, and it has a high value of vaporization. The water evaporation method can be subdivided into a spray type, a ventilated water curtain type, a water-permeable cold plate type, a porous water-permeable grille type, etc., and the total heart component is one (or two) fans. In theory, The water has a vaporization heat value of 2451 J/g at 30 ° C, that is, 1 gram of water can completely absorb 2451 J of heat. If the evaporation process is completed within 1 second and the rate is maintained, the cooling power is equivalent to 245 watts. That is equivalent to the cooling effect of a KC24 single cold window machine. This is a very attractive value.
Since the cooling effect of such fans is mainly determined by the ambient humidity and vertical velocity, this technology is not difficult to obtain good results in dry and hot areas of China. However, in the vast hot and humid areas of the south, due to the high average temperature in summer, the relative humidity is close to saturation, even if the spray of water mist is rarely converted into a vapor state, of course, it can not be said how much heat of vaporization is absorbed, and on the contrary, the degree of humidity in the room is increased. Increase the discomfort of people. In order to improve the cooling effect of this type of humidifying chiller, Fuzhou combined vertical cooling fan proposed perfect measures, such as using a set of cold plates to separate the blown dry air from the blown wet air, and simultaneously exchange heat; The scheme of re-humidifying and cooling is to first absorb moisture into the airflow through the calcium chloride, lithium chloride or quicklime to make it into a dry air with a relative humidity of about 5%, and then humidify it to cool down. Multi-stage dehumidification and humidification, calcium chloride after moisture absorption, etc. can be regenerated under sunlight.
The underground cooling type cooling fan can be subdivided into three types: groundwater, tap water and underground wind according to its cold source. The first two types need to introduce the water flow into the heat exchanger with the fan attached to the room, and then absorb the heat in the room before discharging it. Therefore, the water consumption is large. If a patent says that the water flow per hour needs 180 liters (0.18 tons) or more, this The type of chiller is only suitable for rural and urban households who can drill wells and take water. The tap water type cooling fan is difficult to be accepted by urban residents because of its large water consumption, high water temperature, and poor cooling effect. Underground wind-type chillers are only suitable for households close to civil air defense facilities, basements, etc., and the cold air extracted is often odorous and has no universal significance.
The semiconductor cooling type fan uses the Peltier cold and heat effect, which has the advantages of no noise, fast cooling speed, continuously adjustable cooling capacity, compact structure, no fear of vibration, small size, light weight, long service life, convenient installation and use. . The factors affecting the promotion are low energy efficiency and the need to be equipped with a DC (rectifier) power supply. At present, it is mainly used in the occasion of existing DC power supplies such as cars, boats and airplanes.
There are two options for the refrigerator to take the cold type. One is to install a fan system on the existing refrigerator, making it equivalent to a small power air conditioner, one machine for dual use. The second is to put the refrigerant (cold core) or ice cube processed by the refrigerator into a specially designed fan to blow out cold air, such as using a high-efficiency cold storage core block. Its cold equivalent is 8 times that of ice cubes. The weight of the block is 1.5 kg. The total cooling capacity is 4800kJ, and it can work continuously for 5 hours after being cooled once. Such chillers have limited cooling capacity and are only suitable for small-scale cooling.
There are many patents that propose low-power air conditioning schemes such as air-conditioning accounts, air-conditioner bedspreads, and small air-conditioning rooms. The power consumption is about 200 watts, which is equivalent to the power consumption of refrigerators. The problem is that the energy efficiency of this type of air conditioner is relatively low, the small range is closed, and the air freshness will soon deteriorate.
The solar refrigeration system can be divided into three basic types: adsorption/desorption, absorption and compression. The refrigeration capacity can be obtained according to the principles of compression refrigeration cycle, absorption-evaporation cycle, heat pump or solid adsorption. In theory, the greater the intensity of solar radiation, the greater the cooling capacity, and the outlook seems optimistic. However, due to the generally low COP value of solar chillers, it is reported that if you want to obtain 2000 watts of cooling power, you need to equip 10 square meters of collectors, the cost is as high as 8,000 yuan, it is not realistic to equip urban households.
In addition, there are a few patents that propose a heat pipe refrigeration system using liquid ammonia as a working medium, a gas-fired refrigeration system using liquid ammonia or bromine as a working fluid, and a refrigeration system using a saturated solution of an inorganic salt such as ammonium chloride. The technical proposal, its feasibility of production has yet to be further demonstrated.
