Method for Improving double heat pump hot-water system startup and adjustment performance

Abstract

The invention discloses a novel method for starting and regulating working performances of a modified double heat pump bath hot-water system (i.e. a device for utilizing waste water and waste heat after bath to produce bath hot water). The method is implemented by adding a temperature-balancing tank and an electric heater at the water inlet end to shorten the start-up time and save water, and utilizing a three-way energy efficiency valve and a solenoid valve to regulate the volume of inlet waste water and thus to control the outlet water temperature. The invention has the advantages of high energy-efficiency ratio, rapid heating, and good start-up and temperature-regulation performances; and can work at a temperature below 5 DEG C.

Description

technical field [0001] The invention relates to a new method for improving the start-up and variable working condition adjustment performance of a bathing hot water system based on a heat recovery cycle and a heat pump cycle, which uses waste heat from shower waste water to produce shower hot water, and belongs to engineering thermophysics and heat transfer technology. Background technique [0002] The existing heat pump circulating water heater mainly absorbs heat from the air, releases heat in the condenser to raise the temperature of tap water for human use, and has an energy efficiency ratio of about 3 times. Most of the devices that use waste water waste heat to produce hot water for showers and other purposes are heated by electric heating. Such as expired patent 95202934.0, its shower thermal efficiency is about 2 to 3 times that of a water heater directly heated by electricity. The invention patent (96118737.9) of Dang Kunxuan and Lu Yingmei proposed for the first ...

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Problems solved by technology

[0003] First, the start-up process of the heat pump heat recovery cycle is a process in which the tap water temperature and the ambient temperature gradually rise to the bathing temperature. Due to the thermal inertia of the system, the time from the start-up to the stable supply of hot water for bathing at about 40°C will be longer. As the tap water temperature and the ambient temperature drop gradually elongate: for example, at a room temperature of 20°C, the start-up process of the system is about 3 minutes, and if the temperature drops to 5°C, the start-up time is extended to about 6 minutes. During the process, the water sprayed by the nozzle cannot be used because the temperature is too low, so it is wasted in vain

[0004] Second, in winter in the north, when the temperature of tap water is lower than 5°C, the evaporator of the system will freeze due to the low temperature of the water in the start-up process, making it unusable, and even causing the evaporator to freeze and cause damage to the system; on the other hand, in summer, when When the water temperature and air temperature are close to 30°C, even if the waste water does not go back to the heat cycle, the heat pump cycle alone will have the difficulty that the outlet water temperature is too high and cannot be lowered, which also makes it unusable

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