4.1 Host condensation heat recovery
For occasions where the air supply parameters are strictly controlled and a new cold and heat source is required, heat recovery type cold and hot water units can be selected to produce reheated water while cooling, which is used for supplementary air reheating. In order to ensure the quality of hot water, a water storage tank is usually set up to store the hot water produced by the host.
4.2 Fresh air heat recovery
When the project is in an area with hot summer and cold winter or hot summer and warm winter, in summer, if the supplemental air is not handled properly, the relative humidity in the laboratory is likely to be too high, or even condensation occurs in the room, which will affect scientific research. In order to ensure that the indoor environment meets the design requirements, it is usually necessary to dehumidify the supply air. When the project has waste heat available for utilization, free energy can be used to dehumidify and reheat the supplementary air. If the project does not have relevant resources, you can obtain "free" heat sources and reheat the air by adopting new technologies and new products. The current technology is to add a U-shaped dehumidifying three-dimensional heat pipe in the air-conditioning unit, before and after the surface cooler is wrapped, using the phase change of the environmentally friendly refrigerant filled in the heat pipe to realize energy "transportation".
First, the outdoor high-temperature and high-humidity make-up air passes through the heat pipe before the surface cooler, and the heat pipe is used to pre-cool it, and at the same time, the heat is transferred to the heat pipe after the surface cooler.
Then, after pre-cooling the make-up air, the surface cooler is used for deep dehumidification.
Finally, the supplementary air after deep dehumidification, and the heat pipe after the surface cooler is reheated to reach the design air supply point. At the same time, the cooling capacity in the supplementary air is "carried" to the heat pipe in front of the surface cooler for compensation. The wind is pre-cooled.
By setting up a U-shaped three-dimensional heat pipe, free energy can be used to pre-cool and reheat the supplemental air to meet the indoor humidity requirements and save energy by about 60%.
4.3 Exhaust air heat recovery
The temperature difference between indoor and outdoor in summer is about 10℃, and the temperature difference between indoor and outdoor in winter reaches 40℃, which has great potential for energy saving. Under the premise of ensuring safety and no cross-contamination, a special heat recovery device is used to recover the energy in the exhaust air for pre-cooling or pre-heating and supplementary air.
4.3.1 Three-dimensional heat pipe heat recovery
With the continuous advancement of science and technology, the leakage rate of the three-dimensional heat pipe has been continuously reduced, and the heat exchange efficiency has been continuously improved. For projects with air conditioning units, a three-dimensional heat pipe is usually installed at the entrance of the air supply unit and the entrance of the exhaust fan unit. The recovery device uses the phase change of the refrigerant in the heat recovery device to realize energy transfer.
In summer, the low-temperature air discharged indoors passes through the three-dimensional heat pipe heat recovery device to convert the refrigerant in the heat recovery device from gas to liquid, and then the liquid refrigerant flows to the air supply side by gravity flow. When the liquid refrigerant encounters high-temperature outdoor wind, the liquid state is transformed into a gas state, which absorbs heat and realizes pre-cooling. At the same time, the gas state refrigerant flows to the exhaust side and recirculates.
In winter, the pipeline layout is the same as in summer, but the refrigerant phase change process is just the opposite of that in summer.
4.3.2 Glycol heat recovery
In some projects, the air-supply air conditioning unit is located on the floor and the exhaust fan unit is located on the roof. If three-dimensional heat pipe heat recovery is used, the pre-cooled or pre-heated make-up air needs to be introduced into the air-supply air-conditioning unit with the help of a duct. In view of the fact that the density of the glycol aqueous solution is higher than that of air, when the same energy is delivered, the building space occupied by the water pipeline is much smaller than the building space occupied by the wind pipeline. Therefore, a split-type heat recovery unit is used, that is, a supplemental air glycol heat recovery device is installed in the air-conditioning unit, and an exhaust glycol heat recovery device is installed at the inlet of the exhaust fan, and the two heat recovery devices pass through The seamless steel pipes are connected, the pipeline is filled with a certain concentration of glycol aqueous solution, and the cold/heat in the exhaust air is transferred to the supplementary air through the circulating water pump to realize energy saving.