Three segment type heat exchanger

Abstract

The invention discloses a three-section heat exchanger, which comprises a Freon flow passage and a water flow passage provided with a common flow passage wall; media in the Freon flow passage and the water flow passage reversely flow to finish heat exchange in the common flow passage wall; and the heat exchanger is characterized in that the water flow passage is divided into an over-cooling section, a saturated section and an overheating section which are orderly connected in series from an entry end to an exit end, the saturated section is connected with a circulating water pump in parallel, an inlet and an outlet of the circulating water pump are communicated with an inlet and an outlet of the saturated section respectively, and on / off of the circulating water pump is determined by the temperature of water entering the over-cooling section. The overheating section causes a heat pump hot water unit to obtain a water outlet temperature higher than condensing temperature; because the saturated section enlarges circulating water flow, the condensing pressure becomes low, and a refrigeration system runs stably and reliably; and the over-cooling section improves the condensing condition of the heat pump hot water unit, reduces compression ratio of a compressor, and improves COP value of the refrigeration system.

Description

Technical field: [0001] The invention relates to a water-side heat exchanger of a heat pump water heater unit, in particular to a water-side three-stage heat exchanger of a direct heating air source heat pump water heater unit. Background technique: [0002] Most of the existing air source heat pump hot water units are composed of compressors, wind-side heat exchangers, fans, water-side heat exchangers, throttling components, intelligent control systems and corresponding water systems. The air-side heat exchanger evaporates and absorbs the heat in the air, and after being compressed by the compressor, it condenses and releases heat in the water-side heat exchanger, and releases the absorbed heat into the water system to provide domestic hot water to users. The hot water method has high COP value, energy saving and environmental protection, and good comprehensive economic benefits. [0003] The water-side heat exchanger is generally a casing type or a plate type. The fluid m...

AI Technical Summary

Problems solved by technology

[0005] 1. The outlet water temperature is limited and cannot meet the high water temperature requirements

[0006] The existing Freon refrigeration system has a limit value for the condensation temperature, so the final temperature of the water tank of the circulating heating air source heat pump hot water unit cannot exceed a certain limit value (generally 50°C). When the temperature exceeds this value, the unit’s The pressure and temperature rise sharply, the unit cannot work normally and even cause an accident

[0007] 2. The temperature of the water tank fluctuates greatly, which reduces the effective volume of the water tank and affects the comfort of use

[0010] 1. Under the condition of low ambient temperature and low water temperature in winter, due to the large attenuation of the heating capacity of the unit, in order to obtain a high water temperature, the water flow through the unit is very small, resulting in large fluctuations in the water temperature during the adjustment process, and the condensation pressure of the refrigeration system Either high or low, the refrigeration system is extremely unstable

[0011] 2. Due to the small water flow, higher requirements are put forward for the adjustment accuracy of the flow regulating valve, and the machine cannot reach a stable working state in a short time

During the start-up process, in order to avoid excessive pressure of the machine, the adjustment range of the water flow is large, coupled with the heat loss of the cold machine, a large amount of cold water will be mixed into the water tank, which will affect the subsequent water storage process, and even when the water tank is full of water, the water temperature is still low. Cannot reach the set value

[0012] In order to meet the requirements of use, the above two methods need to be equipped with large water tanks, and the disadvantages of large water tanks are: high cost; limited installation space; more energy is consumed for water tank insulation

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