IX Международная студенческая научная конференция Студенческий научный форум - 2017

Traditional heating systems are becoming less suitable to use and lose their relevance. Burning gas or liquid fuels in boilers, as never before, the budget burden. Substantial savings can be achieved by using heat pumps to heat your home. Such pumps - a complex and high-tech devices for heating and air conditioning. The main feature of such systems is that the heat is taken directly from the ground or air, without burning of any fuel. Electricity is consumed only at coolant job. Modern heat pumps for heating costs no more than 2,5 kW/h of electricity to produce 10 kW of heat.

The principle of operation of the heat pump

Takes heat from a cold body and give it a hotter become possible due to the property of a substance to consume energy during evaporation and to provide it with condensation, as well as to raise its temperature by compression. Prerequisites for boiling and evaporation are created by pressure changes. The working medium is a liquid with a low boiling point - freon. The main parts of the heat pump are the compressor, capillary system, evaporator and condenser. The source of heat for heat pumps is the environment, the energy level of which varies depending on the object's location and the time of day and year. This is determined by the action of solar radiation, geothermal energy, energy rravitatsionnoro field and the Earth's rotation, as well as energy waste heat energy and process plants. Therefore, energy of the environment should be used only in certain places at certain times.

It morut be local with a relatively high temperature energy sources: soil, groundwater and surface water, ambient air, and the energy flows to the alignment of their temperature with the ambient temperature (enerriya solar, waste heat of industrial plants, exhaust air and waste water). Togo Furthermore, the source may be a low-temperature heat accumulated used periodically or after accumulation.

Practical implementation

In direct contact with the evaporator and condenser with external and internal environment is not typical for heating systems based on heat pumps. The transfer of energy occurs in the heat exchangers. Pumped by an external coolant loses heat to the cold evaporator. Hot condenser transmits it to the home heating system.

The effectiveness of such schemes is highly dependent on the temperature difference between the external and internal environments. The smaller it is, the better. Therefore, heat is rarely taken from outdoor air, which can be a very low temperature.

In place of the energy fence installation distinguish the following types:

• "Ground-water";

• "Water-water";

• "Air-water."

As the coolant in the soil and water systems use safe-freezing liquid. This may be propylene glycol. The use of glycol for these purposes is not allowed, since the depressurization system, it will cause poisoning of the soil or aquifers.

Settings "soil-water"

Already at a shallow depth of soil temperature is only slightly dependent on weather conditions, so the ground is an efficient environment. Below 5 meters, the conditions do not change, at any time of the year. There are 2 types of units:

1) Surface

On the site digging a trench extended to a depth below the freezing level. In these rings are arranged plastic pipes solid and covered with earth.

2) Geothermal

Heat transfer occurs at a depth in the well. High and constant temperature in the depths of the earth produce a good economic effect. In the area drilled wells with depths ranging from 50 to 100 m on the calculation of the required amount. For some buildings can be quite 1 well, for others and 5 will not be enough. The borehole heat exchangers omitted probes.

Settings "water-water"

In such systems use energy-freezing water in winter at the bottom of rivers and lakes, or groundwater. There are 2 types of water plants, depending on the place of sale of heat transfer:

1) At the pond

This option is the least expensive in terms of capital investment. Pipeline just sinks to the bottom of a nearby pond and is fixed on the ascent.

2) On the evaporator

Such a device is used in the absence of water bodies in the vicinity. Buryat 2 wells: expenditure and reception. From the first to the second water is pumped through a heat exchanger.

Settings "air to water"

The air exchanger is installed just next to the house or on the roof. Through it, the outside air is pumped. Such systems are less efficient, but cheap. To improve the characteristics of the plant helps in leeward areas.

Heat pumps (compression, sorption, thermometers, gas, inkjet combined) work on different energy sources, so the base for comparison of energy efficiency can serve as a primary energy produced in a fossil or nuclear fuels. The source of heat for heat pumps is the environment, the energy level of which varies depending on the object's location and the time of day and year. This is determined by the action of solar radiation, geothermal energy, energy of the gravitational field and the Earth's rotation, as well as energy waste heat energy and process plants. Therefore, energy of the environment should be used only in certain places at certain times. It can be local with a relatively high temperature energy sources: soil, groundwater and surface water, ambient air, and the energy flows to the alignment of their temperature with the ambient temperature (solar energy, waste heat of industrial plants, exhaust air and waste water). Furthermore, the source may be a low-temperature heat accumulated used periodically or after accumulation. The room temperature may vary slightly from the ambient source temperature, so the low-temperature heating systems are particularly suitable objects for TNU. With proper calculation and feasibility in low-temperature heating systems can be used in virtually all types of heaters and air heating units. Suitable for low-temperature systems are radiant panel devices, combined with the walling. The building heating systems must be purposeful distribution of energy flows at a different kind of energy coupling. They may be in the form of series and parallel connection by means of mixers, heat exchangers and the heat pump. Due to the action of the heat pump heating system increases efficiency while reducing energy intake from outside. It should be borne in mind that the heat pumps require a complex spatial use with the greatest possible duration of operation throughout the year. When designing new systems, district heating schemes can be used combined with heat pumps. Advisable in this case is not only a decrease in the return temperature, but a general decrease in the temperature level, for example, conventional 150 to 20 ᵒС and below. When power supply from thermal power plants use the compression heat pumps with an additional supply of electrical energy it is often uneconomical. It is wise to the central heating system in which the heat pump and energoakkumulyatsionnaya system is used at different times or in parallel. During peak heat pump to the power supply is turned off. At this time, heating is powered completely from the battery. The rest of the heat pump operation, and when a large flow of heat in a heat pump system coupled with energoakkumulyatsionnoy.

The disadvantages of heat pump installations

A major shortcoming of the heat pump can be considered only high capital investments at the stage of procurement of equipment and installation. Price standard heating system with a geothermal heat pump, heat exchanger consists of the cost of work drillers and equipment specific to the installation.

Advantages of heat pump systems

The somewhat higher initial costs are balanced by significant advantages:

• heat pump system is very economical that allows to recoup additional costs in just a few season;

• there are opportunities to implement flexible automated control with a minimum of maintenance;

• comfort of use;

• well suited for installation in living rooms, thanks to the aesthetic and modern design;

• cooling facilities based on the same set of equipment;

• when the cooling operation in addition to the active mode can use a lower temperature natural water and soil for the realization of passive mode without extra energy;

• low power equipment does not require a power cable laying large cross-section;

• no need for permits.

The ability to use existing wiring heating appliances, as well as environmental friendliness, the almost complete absence of noise, full automation of the system, the lack of operating costs (excluding electricity for operation of the unit), safety and reliability. Heat pumps can be successfully used for the heating of single-family detached homes. The essential requirements for their successful application are low-temperature heating system and a significant (about 2 fold) increase in teplozapanels to reduce heat loss of the building. In all of the above listed media cpedy ambient energy can be used as a low-grade heat sources. Ideally, reinforced with additional thermal insulation, the use of solar collectors and batteries in circuit with the heat pump primary energy consumption compared with a conventional solution may be reduced in 3 ... 4 times.

References:

1. L. M. Makhov, A. N. Skanavi, Heating: Textbook for students enrolled in the direction "Construction" specialty 290700, Moscow, 2002.

2. G. Heinrich, H. Nayork, V. M. Nestler, Teplonanosnye installation for heating and hot water supply, Stroyizdat, Moscow, 1985.

3. SNIP 41-01-2003. Heating, ventilation and air-conditioning.

4. http://plusteplo.ru/otoplenie/sistemy-otopleniya/teplovoj-nasos/princip-raboty-teplovogo-nasosa.html

5. http://banivl.ru/teplonasosnye-ustanovki-teplovye-nasosy-alternativnoe-otoplenie-doma

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