A water heating method for maximizing the heat output of heat pump water heaters in winter

Abstract

The invention discloses a water heating method for maximizing heat output of a heat-pump water heater in winter. The water heating method is characterized in that a water heating system of the heat-pump water heater adopts a water heating manner of superposing large direct heating with small circulation, and is designed according to three control principles, the first one is that a water outlet temperature is ensured to increase a volume utilization ratio of a heat storage water tank, the second one is that the optimal condensing pressure of a refrigerant is controlled to ensure the maximization of a heat output power, and the third one is that a water flow speed of a condensing hot-water heater is increased to enable heat exchange capacity to be the optimal; a heating manner is that running water enters a water mixing tank, is mixed with flow-distributing hot water, and is conveyed in the condensing hot-water heater through a circulation pump to be heated, and hot water with an amount equal to a water inlet amount is conveyed to the heat storage water tank through a water outlet flow rate adjustment valve; and a mixed water flow rate is regulated and controlled to meet the three regulation and control principles, relationships among regulation and control parameters are deduced, specific implementations are introduced, and experiments show that the method disclosed by the invention increases a heat output rate by 20-25% compared with traditional direct-heating type and circulation type heat-pump water heaters.

Description

technical field [0001] The invention relates to the field of heat pump water heater technology and energy saving. Background technique [0002] The heat pump water heater uses the refrigerant to undergo a cycle of compression, condensation, throttling, and evaporation. It evaporates in the evaporator, and the low-temperature refrigerant absorbs air energy, condenses in the condenser, and the high-temperature refrigerant heats water to supplement high-grade electric energy during the compression process. , so that zero-level air energy or low-grade cold water energy can be increased to obtain hot water with a higher temperature. The heat of hot water is equal to the sum of input electric energy and absorbed air energy. Therefore, using a heat pump water heater to make hot water is more energy-efficient than using an electric water heater. However, the heat pump water heater has a low coefficient of performance COP, low output thermal power, and a small amount of hot water ou...

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Problems solved by technology

[0005] (3) The industry has been arguing over whether the direct heating heat pump water heater or the circulating heat pump is better than the two heating methods, and there is no clear conclusion. The industry standard only stipulates the test standards for heat pumps with two heating methods

If the initial water temperature of the water tank is mixed with yesterday's remaining hot water, the volume utilization rate of the hot water storage tank will decrease in proportion to the increase of the initial water temperature of the water tank; The water temperature keeps rising, the high and low pressure difference of the refrigerant keeps changing, and the restrictor is fixed, so the matching effect of the refrigeration system is not good, and the irreversible loss of the refrigeration system is large

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