Since the amount of hot water is usually not fixed, and the heat pump is only turned on, the speed of the hot water is basically at a certain flow rate. Therefore, in order to facilitate the use and fully recover the heat of the stove, the heat pump working time is inconsistent with the hot water usage time. In the contradiction, a heat preservation water tank with a volume of 0.5m3 was added to the system, and a bypass valve was installed on the inlet and outlet pipes of the heat preservation water tank. When there is no need for hot water, the hot water is stored in the insulated water tank, and it is provided at any time when needed, and can be directly supplied by the heat pump or the hot water provided by the insulated water tank as needed. Some heat pump water heaters place the condenser directly in the insulated water tank, making the whole device more compact, but it is not easy to obtain hot water of higher temperature, and the whole tank water is heated before use.
It can be seen from the test results that due to the high temperature of the kitchen exhaust gas (above 30e), the heat pump is used for heat recovery to obtain hot water for daily life, and the heating efficiency is mostly above 4.5, which is better than that of ordinary air source heat pump air conditioner. The thermal efficiency (about 3.5) is obviously high, the energy saving effect is obvious, and the water temperature can reach 40e or more after 1 minute after starting, which is convenient and quick. After the research on the heat recovery heat pump of the kitchen, the heat pump recovers the waste heat from the kitchen exhaust and the hot water can meet the needs of kitchen washing and cleaning, without adding additional hot water equipment.
On the basis of using the heat pump to recover the waste heat of the kitchen to obtain the domestic hot water, if the cooling of the kitchen is considered at the same time, the working environment of the kitchen staff is improved, and the hot water P cold air dual-purpose device can be further developed. The compressor, condenser and throttling mechanism of the device can be shared. It is only necessary to increase the heat exchange capacity of the evaporator and design it into two parts. One part of the evaporator handles the kitchen exhaust and the other part handles the indoor return air. In this way, not only the cold air is obtained, but also the amount of hot water produced is increased due to the increase in heat intake (the capacity of the compressor, the condenser and the throttling mechanism should be correspondingly increased by the hot water P cold air dual-purpose heat pump device evaporator layout plus). The device is currently in trial production.
Summarize the use of heat pump to recover the waste heat of the kitchen to obtain daily hot water, which has the advantages of high heating efficiency and obvious energy saving effect. Further development of hot water P cold air dual-purpose heat pump device can not only provide cold air required for kitchen cooling, but also increase The amount of hot water produced. However, it should be noted that such devices have certain limitations in the promotion and use, which is difficult for the general family to accept, and some restaurants and restaurants are more suitable for use. This is because the purchase cost of such devices may not be low, and the average household is more sensitive; in addition, the home kitchen can recover less heat and requires less hot water.
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