Innovative power engineering

shaft transporting to generator is 0.9. And the power of one single float transporting to the generator shaft is :

Pe P0 0.9 0.98 0.9 4.3 kW.

The wave length of the wave is about 50m. To ensure floats won’t interfere with each other and have enough separation distance. Meanwhile, there is phase difference between each float. So set 5 floats in one line in one wave length. Each 10m set one line. Set 5 lines totally. So there are 25 floats on the 50*50 scale. Based on the relationship between the loss of long distance transmission and the distance, set 5 generator sets a regular pentagon in the center of this area. It constitutes a generator system.

This system ‘s total generator output

P = 4.3*25 = 107.5 kW.

So choose 5 generator of 20 kW.

According to statistical data, the average energy flux density of the South China Sea is 10kW/m2. So the absorptivity of energy is:

4. Working Principle and Performance Analysis

The basic working principle of the work is using the float to absorb the potential energy of wave and the vane wheel to absorb the kinetic energy. Energy transported to the bottom transmission mechanism through the transmission rope drives the electrical generator. Through ensuring that every moment has same amount of floats in different phase difference to drive the generator we ensure the efficiency of the generator and the stabilization of the generating quality. Multi-floats structural decreases the size of one single part, the hogging force of wave and strengthens the ability of wave/wind resistance.

According to the designing scheme, we made the physical model as shown in the Fig. 6. The test procedure is shown in the video. We

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simulate the load with LED. During the test procedure, LED illuminated by bright lights and the electricity generation performance is good. Under the circumstances of increased waves, the float also operated steadily. So the model’s ability of wave/wind resistance is good.

Fig. 6. Model physical chart

5. Innovation Points

The device uses array type floats. It takes big energy absorption plant apart into several smaller one. The size of one single device is greatly decreased. Also decreased is the hogging force of the wave and strengthened is the ability of wave/wind resistance.

Several cells work in different phase. They will complement each other and improve the generating quality and stabilize the generator speed.

It doesn’t need land surface which will be more appropriate for island. And its modular structure will be more convenient for power expansion, installation and maintenance.

6. Advantages

Against background of applying medium-and-small-sized energy systems for island, compared to existing techniques of the same kind, this work has two major advantages:

In terms of stability, the existing devices costs a lot in manufacturing, installation and maintenance. And they are easy to be damaged, because their monomer structure is too big to bear large

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force. Their ability of wave/wind resistance is poor. And this work uses array-type floats. It is small for one single device and is good in resisting large wave and wind. Its modular structure will be more convenient for installation and maintenance.[10]

In terms of generating quality, most existing devices are largescale monomer structure or several devices working at the same time. They are poor in generating quality. And this work has different floats working in different phases. They will complement each other to stabilize the generator speed and improve the generating quality.

References

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NESTED ENERGY-SAVING WATER BOILER

BASED ON AIR-SOURCE HEAT PUMP

Yu Tianning, Wang xuchen, Li Haoran, Li Songqi

Northwestern Polytechnical University, Xi’an, P.R.China

The nested energy-saving water boiler based on air-source heat pump is a kind of multifunctional water boilers which can provide washing water in 60 °C and drinking water in different temperatures. It use air-source heat pump as a major heating mode, and electric heating as a minor mode. It combines respective advantages of different heating modes, therefore, this water boiler can use power efficiently.

Worldwide energy shortages and requirements of sustainable development urge air-source heat pumps to be supported by the policy as an efficient energy-saving device. In addition, the improved capacity of the power system, technological advances and beneficial national policies bring a good opportunity for the development of air-source heat pump water boiler.

The working principle of the heat pump is as follows.

a)The working refrigerant, in its gaseous state, is pressurized and circulated through the system by a compressor.

b)On the discharge side of the compressor, now hot and highly pressurized vapor is cooled in a condenser and releasing heat, until it condenses into a high pressure, moderate temperature liquid.

c)The condensed refrigerant then passes through a pressurelowering device, such as an expansion valve.

d)The low pressure liquid refrigerant then enters another heat exchanger, the evaporator, in which the fluid absorbs heat and boils.

e)The refrigerant then returns to the compressor and the cycle is repeated.

This boiler’s key technology is the following aspects. Firstly, the use of multi-layer design and mutually nested structure in this boiler can achieve efficiently use of energy and reduce energy loss. Secondly, heat pump and electric heating are reasonably controlled so that water

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temperature in each tank will be maintained at a preset temperature range. Thirdly, the appropriate heat-preservation materials can reduce heat dissipation. Fourthly, the single chip circuit and various sensors can control solenoid valve opening and closing, thus the water level is maintained at the proper range.

This nested energy-saving water boiler is made up of drinkingwater tank, washing-water tank, ice-water tank and heat pump accessories box. Covering the water tanks with polyurethane heatpreservation materials is beneficial to minimize heat dissipation, so as to achieve energy-saving.

Washing-water tank surrounds the outside of the drinking-water tank, equipped with a heat pump condenser tube. It has comparatively large volume and is preheated by the heat pump to about 55 °C. In this working temperature condition, the heat pump can work efficiently and its COP is higher than 2.5.

Drinking-water tank is divided into three-tier structure. The upper part is the boiling tank, in which preheated water from the washingwater tank can be heated to boil by an electric heating pipe, so it can achieve a drinkable condition. The middle part is the heat-preservation tank, in which boiled water can be maintained at 95 °C by an electric heating pipe, this tank can provide drinking boiling water and avoid unhealthy repeated boiling. The bottom part is the warm-water tank, in which water reduce temperature from 95 °C to about 60 °C by a heat exchange with the outside washing-water tank, thus it provide users with drinkable warm water by means of the heat dissipation.

Ice-water tank is located under the washing-water tank, equipped with a heat pump evaporation tube, drinkable warm water can be cooled by heat pump, the desired effect is providing water in about 15 °C.

The heat pump accessories box is located at the bottom of the boiler, including heat pump compressor, electromagnetic expansion valve, shell and tube heat exchangers, heat pump evaporator tubes, exhaust fan, boiler’s microcontroller, etc.

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Furthermore, we have conducted a survey of the boiler consumer market, there are several problems found in the current boiler. Such as high energy consumption, no temperature choice, unreasonable working control, etc. This nested energy-saving water boiler can solve such problems and meet the needs of customers.

The nested energy-saving water boiler based on air-source heat pump can be mainly used instead of the traditional electric heating water boiler in occasions with large-scale flow of people, its economy and energy efficiency is very significant and should be popularized widely.

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