RU2846151C1 - Solar electric heating plant - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: invention relates to the field of agriculture, in particular, to equipment for heating of production and auxiliary premises of agricultural purpose, in particular, for livestock premises. Installation contains massive Trombe-Michel wall with an outer dark side that absorbs solar radiation, protected from the outside by glazing with an air gap, air inlet and outlet openings, lower and upper air dampers, a room air temperature sensor, a backup heat source consisting of a housing, an air duct, a heat accumulator, tubular electric heating elements and an electric fan, control unit, to which the lower and upper air dampers, the room air temperature sensor and the electric fan are connected. Inner side of the Trombe-Michel wall is covered with a heat-insulating layer, an air temperature sensor is installed in the air gap, the housing of the back-up heat source is closed from the outside with heat insulation, and an additional air flap is installed in the air channel, wherein the air temperature sensor in the air gap and the additional air flap are connected to the control unit.

EFFECT: disclosed is a solar electric heating installation.

1 cl, 1 dwg

Description

The invention relates to the field of agriculture, namely to equipment for heating production and auxiliary premises for agricultural purposes, in particular for livestock premises.

Active and passive heating installations for heating of solar heating rooms of buildings are known. Based on theoretical and natural tests, it has been established that the development of solar heating systems is promising. It will save a large amount of organic fuel, improve the environmental situation.

A characteristic feature of active heating systems is the presence of a solar energy collector, heat accumulator, additional energy source, pipelines, heat exchangers, pumps or fans and devices for their automatic control and management. In passive heating systems, the role of the solar collector and heat accumulator is usually performed by the enclosing structures of the building themselves, and the movement of the coolant (air) is carried out due to natural convection without the use of a fan.

Comparison of active and passive heating systems allows to identify their advantages and disadvantages. The advantages of active systems are related to the ease and flexibility of their integration with the building and the possibility of automatic control of the heating system, as well as the reduction of heat losses.

The disadvantages of active heating systems are the lack of reliability of the equipment, including the automatic control system, its improper installation and assembly, the complexity of maintenance, the risk of freezing and corrosion, as well as their high cost.

Passive heating systems are simple, reliable in operation and inexpensive.

The disadvantages of passive solar heating systems include difficulties in maintaining the temperature regime necessary to ensure thermal comfort in heated rooms, the impossibility of using them at night, and low efficiency.

A solar house is known, comprising enclosing wall structures and a roof with solar radiation reflectors installed parallel to the roof surface and double-sided solar modules installed in the meridional direction in a protective glass shell on each side of the module with the working surfaces oriented to the east and west; on one side of the module, over the entire area of the working surface, in thermal contact with the glass protective shell, a sealed chamber made of transparent material for pumping a coolant transparent to solar radiation is fixed, connected to the hot water supply and heating circuit of the solar house (RU Patent No. 2755204, IPC F24S 90/00, H02S 10/30, published on 09/14/2021, Bulletin No. 26).

The disadvantages of the well-known solar house are its high cost, insufficient reliability, difficulties in maintaining the temperature regime, especially at night, and the complexity of the design of heat-accumulating elements.

A hybrid solar module for generating heat is known, comprising a protective glass covering, connected solar cells and a heat exchanger connected to a hot water supply and heating system of a building, the heat exchanger is made in the form of an air collector with channels for an air coolant in a housing transparent to solar radiation and is installed over the area of the protective glass covering, wherein the protective glass covering and the heat exchanger in the form of an air collector are located on both sides of the connected double-sided solar cells, wherein for heating the building the air collector is connected via a heat-insulated air duct with a fan to the air heating system of the building, for hot water supply the air collector is connected via a heat-insulated air duct with a fan and an air-to-water heat exchanger to the hot water supply and heating system of the building, and the connected solar cells are connected via an inverter to an electric water heater of the hot water supply system of the building (RU Patent, No. 2763117, IPC H02S 10/30, F24D 10/09, published. 11.01.2022, bulletin No. 2).

The disadvantages of the well-known hybrid solar module are the absence of a heat-accumulating element in the module, which causes significant fluctuations in air temperature in the heated room.

A recuperative supply electric heating unit is known, in which the outside air enters a channel through an air intake, where it is heated by warm internal air through the finned outside walls of the channel (Rayak M.B. Ventilation of livestock buildings. Review information. Issue 4.M., VNIIIS, 1983). After mixing recirculated air with the outside air, the mixture is heated in an electric heater. After passing through the heat accumulator, the supply air partially enters the animal placement area in the heated room, and partially enters the upper zone of the room through the channel. The presence of a vertical channel of warm air increases the gravitational pressure to overcome the aerodynamic resistance of the heat recovery unit, provides additional heating of the cold air through the common heat-conducting wall. The heat-accumulating attachment allows heat to accumulate during the period of nighttime reduction in electricity consumption, which is then used in peak loads.

The disadvantage of the known recuperative supply electric heating unit is the impossibility of using solar radiation to heat the room, high energy costs, the impossibility of maintaining the required uniform heating temperature and using the night reduced tariff for electricity, as well as the low efficiency of the unit.

An individual solar installation with a glazed heat-accumulating southern wall (Trombe-Michel wall), painted black or another dark color, is known, having several design options (Kharchenko N.V. Individual solar installations - M.: Energoatomizdat, 1991 - 208 p. ill.). Solar radiation penetrating through the glazing is absorbed by the wall surface, accumulates in the mass of the wall, which causes an increase in the wall temperature, which heats the air in the room.

The disadvantage of the well-known individual solar installation is that the heat accumulated during the day is transferred with some delay into the premises by means of radiation and convection; for example, with a concrete wall thickness of 200 mm, the delay in heating the room is 5 hours.

The closest to the proposed invention is a passive solar heating system (Trombe-Michel wall), comprising a massive Trombe-Michel wall with an outer dark side that absorbs solar radiation and is protected from the outside by glazing, an air gap, openings for air inlet and outlet, lower and upper air dampers, a room air temperature sensor, a control unit with which the lower and upper air dampers and the room air temperature sensor are connected, a duplicate heat source consisting of a housing, an air duct, a heat accumulator, tubular electric heating elements and an electric fan, Electric fan. (Solar heating and cooling systems / R.R. Avezov, M.A. Barsky-Zorin, I.M. Vasilyeva et al.; Ed. by E.V. Sarnatsky and S.A. Chistovich. - M. Solar heating and cooling systems. Stroyizdat, 1990. - 328 p. -32.: ill.). At the floor and ceiling level there are openings for air inlet and outlet, equipped with air dampers. Solar radiation is absorbed by the outer surface of the Trombe-Michel wall, which heats up and in turn heats the air in the gap between the glazing and the wall. Heated air enters the heated room through the upper opening, cools down and returns to the gap through the lower opening. Thus, thermosiphon air circulation is carried out in the system. Automatic regulation of air temperature is achieved by changing the amount of incoming solar energy and by changing the heat output of the backup heat source (an electric storage device with a fan).

The disadvantages of the well-known solar heating system are high energy costs, large losses of thermal energy in the Trombe-Michel wall, the inability to maintain the required heating temperature and the use of a reduced night tariff for electricity when heating the premises.

The technical task of the proposed invention is to reduce energy costs for heating the premises, maintain the required heating temperature, reduce heat energy losses, use the night-time reduced tariff for electricity and increase the efficiency.

The technical result is achieved in that in a solar electric heating installation containing a massive Trombe-Michel wall with an external dark side that absorbs solar radiation and is protected from the outside by glazing, an air gap, openings for air inlet and outlet, lower and upper air dampers, a duplicate heat source consisting of a housing, an air duct, a heat accumulator, tubular electric heating elements and an electric fan, room temperature sensor, control unit, which is connected to the lower and upper air dampers, room temperature sensor, electric fan,according to the invention, the inner side of the Trombe-Michel wall is covered with a heat-insulating layer, and an air temperature sensor is installed in the air gap, the body of the backup heat source is covered from the outside with thermal insulation, and an additional air damper is installed in the air duct, while the air temperature sensor in the air gap and the additional air damper are connected to the control unit.

The invention is illustrated by a drawing which shows a general diagram of a solar electric heating installation.

The solar electric heating installation comprises a massive wall with a dark outer side of the Trombe-Michel 1 with a heat-insulating layer 2, protective glazing 3 with an air gap 4, an air inlet 5, an air outlet 6, a lower air damper 7, an upper air damper 8, an air temperature sensor 9 in the air gap and a backup heat source 10. The backup heat source 10 comprises a housing 11 with thermal insulation 12, a heat accumulator 13, tubular electric heating elements (TEN) 14, an air duct 15, an additional air damper 16 and an electric fan 17. The electric fan 17, an air temperature sensor 9 in the air gap 4 and an air temperature sensor 18 in the room, lower 7, upper 8 and additional 16 air The flaps are connected to control unit 19.

The room is limited by enclosing structures (ceiling, walls, floor) 20.

In the heated room opposite the protective glazing 3, a massive (concrete) Trombe-Michel wall 1 (heat accumulator from solar radiation) with a dark outer side is installed. On the inner side of the wall 1, a heat-insulating layer (mineral wool) 2 is made. Between the glazing 3 and the Trombe-Michel wall 1, there is an air gap 4, in which the heat carrier (air) is heated by solar radiation to heat the room. The inlet opening for cooled air 5 is located at the floor level, and the outlet opening for heated air 6 is located at the ceiling level of the room. Adjustable lower 7 and upper 8 air dampers are installed in the inlet 5 and outlet 6 air openings, respectively.

An air temperature sensor 9 is installed in the air gap 4. The backup heat source 10 consists of a housing 11 covered on the outside with thermal insulation (mineral wool) 12, a heat accumulator 13 with tubular electric heating elements (TEN) 14, an air duct 15 in which an additional adjustable air damper 16 is installed, and an electric fan 17. The air temperature sensor 18 is installed in the heated room with enclosing structures (ceiling, walls, floor) 20.

The solar electric heating system works as follows.

Solar radiation is absorbed by the dark side of the Trombe-Michel wall 1, which heats up and, in turn, heats the coolant (air) in the air gap 4 between the glazing 3 and the wall 1. The thermal insulation layer 2 on the inner side of the Trombe-Michel wall 1 reduces the loss of thermal energy accumulated in the wall 1.

At night, heated air enters the heated room through outlet 6, cools down and returns to the air gap through inlet 5. When the air temperature in the air gap 4, measured by temperature sensor 9 in the air gap, exceeds the air temperature in the heated room, measured by temperature sensor 18 in the room, air dampers 7 and 8 open and the air heated by the sun begins to circulate in the room through openings 5 and 6. The cooled air in the room returns to the air gap 4 through inlet 5 with the lower air damper 7 open. As soon as the air temperature in the air gap 4, measured by temperature sensor 9, falls below the air temperature in the room, dampers 7 and 8 close. If the room air temperature measured by temperature sensor 18 is lower than the set value, then air damper 16 in air duct 15 of backup heat source 10 will open and electric fan 17 will be switched on. With the help of electric fan 17, with open additional air damper 16, air, passing through air duct 15 along the surface of heat accumulator 13 with tubular electric heating elements (TEN) 14, is heated. Heated air, coming out of air duct 15, heats the room with enclosing structures (ceiling, walls, floor) 20, in which the required heating temperature is controlled and provided by control unit 19.

The backup heat source 10 with thermal insulation 12 is charged during the night hours when electricity is supplied at a reduced rate.

When switched on, tubular electric heating elements 14 heat up heat accumulator 13 of backup heat source 10 during the period of reduced night tariff for electricity, in which thermal energy is accumulated (charged). In this case, air dampers 7 and 8 close and air circulation in air gap 4 stops.

When the solar heating system is in operation, the air in the room is alternately heated. During the day, the Trombe-Michel wall 1 is heated by solar radiation, and the room is heated by the backup heat source 10. At night, the Trombe-Michel wall 1 gives off the accumulated heat for heating the room, and the backup heat source 10 consumes off-peak (cheap) electricity and accumulates heat in the heat accumulator 13.

An example of the implementation of a solar electric heating system.

The heating of the livestock building (calf house) was carried out by a solar electric heating installation containing a massive wall 1 of the Trombe-Michel type (solar energy heat accumulator), the inner side of which is covered with a heat-insulating layer 2 and a backup heat source 10 (heat-electric accumulator), the body 11 of which is covered on the outside with thermal insulation 12.

Calculation parameters of solar electric heating system

Thermal power of the Trombe-Michel wall, kW 8-10 Temperature of heating of Trombe-Michel wall, °С 40-45 Electric power of tubular electric heating
elements, kW 5

When the solar heating system is in operation, the air in the calf house is heated. During the day, the Trombe-Michel wall 1 is heated by solar radiation to a temperature of 40-45°C and maintains the temperature due to the heat-insulating layer 2 on the inner side of the wall 1, and at night the calf house is heated by the accumulated heat. At night, the heat accumulator with tubular electric heating elements 14 of the backup heat source 10, the body 11 of which is covered with thermal insulation on the outside, is charged, consuming off-peak (cheap) electricity. The air temperature in the calf house is 17°C around the clock.

In this way, the calf house is heated using solar energy and cheap electricity.

The technical and economic assessment showed that when using a solar electric heating system to heat a calf barn, energy costs for heating the premises are reduced by 15-20%, and the efficiency of the system increases by 10-15% compared to the prototype.

The proposed invention allows to reduce energy costs for heating a livestock building, reduce heat energy losses, maintain the required room heating temperature, use a reduced night tariff for electricity and increase the efficiency of the installation.

Claims (1)

A solar electric heating installation comprising a massive Trombe-Michel wall with an outer dark side absorbing solar radiation, protected from the outside by glazing with an air gap, openings for air inlet and outlet, lower and upper air dampers, a room air temperature sensor, a duplicate heat source consisting of a housing, an air duct, a heat accumulator, tubular electric heating elements and an electric fan, a control unit to which the lower and upper air dampers, the room air temperature sensor and the electric fan are connected, characterized in that the inner side of the Trombe-Michel wall is covered with a heat-insulating layer, an air temperature sensor is installed in the air gap, the housing of the duplicate heat source is closed from the outside by thermal insulation, and an additional air damper is installed in the air duct, wherein the air temperature sensor in the air gap and the additional air damper are connected to the control unit.