Air source heat pump double-water-tank hot water system and control method thereof

Abstract

The invention relates to an air source heat pump double-water-tank hot water system and a control method. The air source heat pump double-water-tank hot water system comprises a variable-frequency water supply pump, a hot water tank, a warm water tank and a parallel host which are connected in sequence, and further comprises a water return valve and a water replenishing valve which are connected with the warm water tank; the hot water tank, the warm water tank and the parallel host are sequentially connected to form host-water tank circulation; the warm water tank, the hot water tank, the variable-frequency water supply pump and the water return valve are sequentially connected to form water tank-tail end circulation; and the parallel host comprises a plurality of parallel branches which are independently controlled or not independently controlled, and different heat supply modes are achieved by opening a specific number of parallel branches, so that different tail end load requirements are met. Compared with the prior art, the double-water-tank scheme is adopted, so that the mixing loss among return water, replenished water and hot water is reduced; and meanwhile, the water inlet temperature and the water outlet temperature of the heat pump are reduced, the condensation temperature of the heat pump can be well reduced, and the energy efficiency of the heat pump unit is improved while water consumption of a user is guaranteed.

Description

technical field [0001] The invention relates to a hot water system and a control method thereof, in particular to an air source heat pump double water tank hot water system and a control method thereof. Background technique [0002] At present, large and medium-sized buildings (such as office buildings, hospitals, dormitory buildings, teaching buildings, etc.) often use a centralized heating zone system to provide domestic hot water. The system takes a certain building or a building in a certain area as a unit, mainly medium and large hot water storage tanks, and provides heat sources in a centralized and unified manner to form a central hot water supply station. The central hot water supply station sends hot water to each district through hot water pipes in a network layout, and then sends hot water to each water distribution point through the transmission and distribution pipelines of each district. With people's emphasis on energy conservation and environmental protectio...

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Problems solved by technology

[0005] In actual use, most of the existing heat pump hot water systems have the following three problems: first, the high temperature hot water (about 55°C) produced by the heat pump, the medium temperature return water (about 40°C) of the end pipe network, and the supplementary water The low-temperature cold water (about 15°C) in the pipeline is uniformly sent to the hot water tank, and there is a loss of mixed water; second, multiple heat pump hosts and heat collection pumps use the same controller, which can only be started and stopped as a whole, which is not conducive to the operation under partial load. The unit is controlled, and the loss of starting and stopping is large; thirdly, in order to resist the temperature drop of mixed water and avoid frequent starting and stopping, the heat pump host needs to supply higher water temperature (about 55 ℃) to deal with the terminal water supply (about 50 ℃), and the high water supply temperature increases The condensing temperature of the unit reduces the energy efficiency of the heat pump host

The dual water tank system used in the above patent only divides the water tank into the main water tank and the auxiliary water tank. The heat pump only heats one of the water tanks at a time, and uses the method of staggered peak storage to ensure the water temperature and save energy consumption. The double water tanks are not really used. The advantages of the system, and the above patents do not consider the situation that multiple heat pumps start and stop at the same time

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