Method for Producing Hot Water Utilizing Combined Heat Resources of Solar Energy and Heat Pump in the Manner of Heating Water at Multilpe Stages and Accumulating Energy and a Device Especially for Carrying Out the Method

Abstract

A method for producing hot water and a device especially for carrying out the method are provided. The method utilizes combined heat resources of solar energy and heat pump in the manner of heating water at multiple stages and accumulating energy. The device comprises solar energy collector, heat pump, electrical heater, water tank, and control unit. The device also includes water-heating tanks with multiple stages. A heating means with multiple stages at different temperatures is formed either by the solar energy collector or by the collector and the heat pump. The outputting end of the two or more heating stages constituted by the solar energy collector or by the collector and the heat pump is connected through ducts to the corresponding water-heating tanks. A predetermined amount of produced water heated at multiple stages is respectively stored in the water-heating tanks. Compared with the prior art, the present invention is endowed with the performance of making use of the solar energy to the greatest extent and utilizing off-peak electricity more efficiently as a supplementary heating means. Furthermore, the arranging fee of the device is reduced and its adaptation of mounting is improved.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a field of utilizing solar energy, and more particularly to a method for producing hot water utilizing combined heat resources of solar energy and heat pump in a manner of heating water at multiple stages and accumulating energy and a device especially for carrying out the method.BACKGROUND OF THE INVENTION[0002]The sun generates a large amount of energy. The radiant energy reaching the earth's surface from the sun each year equals to the energy generated by about 130 trillion tons of standard coals, but it is still dispersal, discontinuous, and unstable. Although the total amount of solar radiant energy reaching the earth's surface is great, its energy-flux density is very low. So a large area is needed to receive the radiation in order to get a certain radiant power. The discontinuance and instability means that the solar radiant energy is restricted by natural conditions such as days and nights, seasons, geographical la...

AI Technical Summary

Benefits of technology

[0006]A main object of the present invention is to provide a method for producing hot water utilizing combined heat resources of solar energy and heat pumps in a manner of heating water at multiple stages and accumulating energy, so as to produce hot water by utilizing solar energy, heat pumps or electrical heaters in a timesharing mode. Upon meeting the requirements of supplying hot water at or above 45° C. for 24 hours a day and 365 days a year, the solar energy is utilized to the maximum extent before using the energy of the heat pump or the off-peak electricity. Therefore, a predetermined amount of water is produced at a lowest cost in a manner of heating at multiple stages, which is used for energy accumulation and supplying of hot water at different temperature levels in the timesharing mode. If the mounting area for the collector is inadequate, an output water temperature for the collector can be set to a secondary level to enhance the collecting efficiency, which also solves the problem of load distribution caused by mounting water tanks on the roof collectively, reduce the arranging fee, and expand the adaptation of mounting.

[0007]Another object of the invention is to provide a device especially for carrying out the heating method. The device is a combination of heating structures working in a timesharing mode, including solar energy collectors, heat pumps, electrical heaters, water tanks, and control unit. Upon meeting the requirements of supplying hot water at or above 45° C. for 24 hours a day and 365 days a year, the solar energy is utilized to the maximum extent before using the energy source of the heat pump or the off-peak electricity. Therefore, a lowest cost is achieved by heating water at multiple stages, and the hot water produced by heating in advance and by heating at multiple stages in a timesharing mode is used for energy accumulation and supplying water in the timesharing mode according to different temperature level settings. If the mounting area for the collector is inadequate, an output water temperature of the collector can be set to a secondary level to enhance the collecting efficiency, which enables the energy accumulation water tanks to be arranged separately, reduces the arranging fee, and expands the adaptation of mounting.

Problems solved by technology

The radiant energy reaching the earth's surface from the sun each year equals to the energy generated by about 130 trillion tons of standard coals, but it is still dispersal, discontinuous, and unstable.

Although the total amount of solar radiant energy reaching the earth's surface is great, its energy-flux density is very low.

The discontinuance and instability means that the solar radiant energy is restricted by natural conditions such as days and nights, seasons, geographical latitudes, altitudes above sea level, as well as random factors such as clear, gloomy, cloudy, and rainy days.

The energy used for building, such as for producing hot water, can be generated by low-ordered renewable energy sources; otherwise, it would be a waste of power if the high-ordered electric energy is used.

Since the cold water will be input at any time, it is impossible to supply a certain amount of hot water above 45° C. for 24 hours a day and 365 days a year if a non-heat storage water tank of a normal size is used.

Moreover, in sunny days, as the temperature at the upper part of the heat storage water tank gradually goes up, the energy collecting efficiency of the solar energy collecting system declines gradually from noon.

Therefore, the overall thermal performance of the system is quite low.

If the energy is accumulated by means of enlarging the volume of the heat storage water tank, the water in the lower part always has a low temperature, which does not make sufficient contributions for the everyday output of hot water.

Besides, the water at a lower temperature gets bacteria more easily, and gets the supplied water being polluted.

Furthermore, the hot water can be easily mixed with the cold water if no separation and heat preservation technique is used, so the water in the upper part of the tank does not easily reach the required output temperature, and the water tank is too large to be fully utilized.

In addition, the hot water chamber and the cold water chamber are arranged independently for seasonal use, which reduces the application rate greatly, but increases the arranging fee.

However, the efficiency of the electric heat pump is limited by the required temperature and the temperature range of the hot source, and it will be frosted below the critical temperature.

If the temperature difference in heating is too large, it will be easily damaged.

Moreover, it's preferred to use off-peak electricity to produce hot water with the electric heat pump, as the electrical power is in shortage.

However, the water-heating device in this technical solution still has some problems, for example, the solar energy cannot be fully utilized when the area for installing the solar energy collector is limited, and meanwhile, the heat pump must be used to make up the insufficient part where the solar energy is insufficient.

However, it is difficult to get sufficient off-peak electricity at night for family users whose lead-in current capacity is fixed.

Meanwhile, the water tank must be relatively large to realize the effects of accumulating the energy and reducing the cost, which increases the arranging fee for the water-heating device.

For a large-scale concentrated water-heating device, enlarging the volume of the water tank not only increases the arranging fee, but also brings the problems of mounting on the roof and support capacity of the mounting surface.

Moreover, the area for mounting the solar energy collector is reduced, so the adaptation of mounting is affected.

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