About solar heating, cooling, hot water triple supply system
With the development of social economy, energy and environmental issues have become the "bottleneck" restricting the development of the world economy. At present, our country is still in the single utilization stage of energy structure such as coal-to-electricity and coal-to-gas in terms of industrial applications such as building heating, air conditioning and refrigeration, power generation, and hot water supply. my country is an energy-scarce country, and the application of clean renewable energy to achieve the effect of energy saving and emission reduction is urgent. The construction and promotion of solar heating, refrigeration, and hot water triple supply systems can effectively change my country's low utilization of clean energy, serious environmental pollution, and shortage of conventional energy sources. Has good economic and ecological benefits.
01 principle
Solar heating, cooling, and hot water triple supply (hereinafter referred to as "triple supply") system refers to the conversion of solar energy into heat energy through a solar heat collection system, which is stored in an energy storage device, and then transported to the heating terminal, cooling terminal, and The hot water terminal (such as radiator, floor radiation, radiant ceiling, fan coil, shower, washstand, etc.) provides the building with the functions of winter heating, summer cooling, and year-round hot water. The working principle of the tri-generation system is shown in Figure 1.
01 principle
Solar heating, cooling, and hot water triple supply (hereinafter referred to as "triple supply") system refers to the conversion of solar energy into heat energy through a solar heat collection system, which is stored in an energy storage device, and then transported to the heating end, cooling end, and The hot water terminal (such as radiator, floor radiation, radiant ceiling, fan coil, shower, washstand, etc.) provides the building with functions of heating in winter, cooling in summer, and hot water throughout the year.
02 Advantages of the triple supply system
The triple-supply system is divided into solar heating circulation system, refrigeration circulation system, and hot water circulation system.
(1) The tri-generation system is an environmental protection project. It is different from ordinary single heating, cooling, and hot water in the heat source, that is, ordinary heating uses coal, electricity, oil, gas, etc., while the triple power system uses non-polluting solar energy and air heat and other renewable energy sources.
(2) The solar energy system has significant economic benefits. The tri-generation system generally recovers the investment cost in 3-5 years, and its service life is generally about 20 years, so the economic benefits are very significant.
(3) Energy saving and emission reduction. The triple-supply system can realize heating in winter, cooling in summer and domestic hot water, and each subsystem can be operated independently with a modular combination, scientifically and rationally adjusted according to the needs of different periods, and can also be operated online. Fully automated control and remote monitoring, users can directly switch and adjust each system through a mobile phone application to maximize resource utilization.
(4) The various subsystems of the triple-supply system are connected in the form of heat exchangers, and the circulating media between the systems are not in direct contact, which ensures the clean water quality cycle and reduces pollution. The whole system has the characteristics of reasonable utilization of energy efficiency, low loss, low pollution, flexible operation and good system economy.
(5) Turn on auxiliary energy when solar energy cannot meet the demand of system energy consumption. Auxiliary energy is equipped with different types according to the actual situation of the area. For example, heat pump auxiliary, electric boiler auxiliary, gas auxiliary and other multi-energy complementary to realize comprehensive utilization of energy.
(6) The triple power system is a solution based on the concept of energy cascade utilization, using solar energy as the main energy source, and coordinating and combining to meet the demand for heating in winter, cooling in summer, and hot water throughout the year. The system is suitable for large buildings such as schools, hotels, villas, offices, hospitals, gas stations, factories, breeding greenhouses, etc. due to its proximity to users, cascade utilization, high primary energy utilization efficiency, environmental friendliness, and safe and reliable energy supply. Wide attention and favor of the majority of users.
03 Main components of the triple supply system
3.1 Collector
As a component of solar heat utilization, collectors mainly include four types: air-type energy storage solar collectors, flat-plate solar collectors, all-glass vacuum tube solar collectors, U-tube solar collectors . Among them, the air-type energy storage solar collector, as a solar collector using air as the medium, has a fast heating speed, easy maintenance, low cost, leakage does not affect the operation of the system, and does not require antifreeze, anticorrosion, and has a long life. Advantages, and easy to achieve integration with buildings; Flat plate collectors have simple structure, strong resistance to compression and external impact, and low failure rate, but their insulation and thermal performance are not as good as vacuum tube collectors, and anti-freezing, leakage, and scaling must be considered The heat exchange efficiency of vacuum tubes and U-tube collectors is relatively high, but in winter, anti-freezing, overheating in summer, scaling and corrosion should be considered.
3.2 Energy storage device
The energy storage device is mainly used to store the heat energy absorbed by the collector and as a transfer station to transport the heat energy in the form of hot water to the end of the heating, cooling and domestic hot water system. The energy storage device is small in size and light in weight. It has superior heat storage and insulation performance, good heat conduction performance; stable heat storage and release performance, long-term use without attenuation and pollution.
3.3 Auxiliary energy
Auxiliary energy types: oil-fired boilers, gas stoves, biomass boilers, coal-fired boilers, electric heating, (with built-in electric heating in the water tank or external electric heater), heat pump.
Coal-fired boilers take a long time to start and stop, it is difficult to adjust output, it is difficult to realize automatic control or unattended, and it pollutes the environment. Oil and gas boilers are easy to control, easy to adjust, and easy to realize automatic control operation, but the equipment room needs to meet the fire protection requirements, and the fuel cost is high. The use of heat pumps is low cost and easy to control, but the initial investment in equipment is high. In addition, the use of ordinary air source heat pumps in the north is relatively low in energy efficiency in winter. Electric heating equipment is easy to install and easy to control. It is the most commonly used auxiliary heat source for solar water heating systems, but its operating costs are relatively high, and sometimes due to the need for electricity to increase capacity, system investment will increase. In summary, when selecting auxiliary heat sources, various factors must be considered comprehensively.
3.4 Piping
The pipes and fittings used in the triple-supply system should meet the requirements of current industry products, and the working pressure and working temperature of the pipeline should not be greater than the allowable working pressure and working temperature established by the product standard. The pipes of the solar heat collection system can use steel pipes, thin-walled stainless steel, plastic steel hot water pipes, plastic and metal composite pipes, etc. The antifreeze system with ethylene glycol as the main component should not use galvanized steel pipe. Hot water pipes should be corrosion-resistant and meet sanitary requirements. Generally, thin-walled copper pipes, thin-walled stainless steel, plastic hot water pipes, plastic and metal composite pipes, etc. can be used. During design, auxiliary equipment such as exhaust devices, drain devices, thermometers, pressure gauges, safety valves, expansion tanks, etc. shall be installed at necessary positions of the system pipeline. The closed system should be equipped with an expansion tank or a pressure relief valve.
3.5 Pipeline insulation
The connecting pipes, water tanks, and water supply pipes of the heat collection system of the triple power supply system should be insulated. Commonly used insulation materials include rock wool, glass wool, polyurethane foam, rubber foam and other materials. Requirements for selection of pipe insulation materials:
1) The allowable use temperature of insulation material products should be higher than the maximum temperature of the medium used by the solar energy system;
2) Organic matter should not be used as thermal insulation materials to avoid insects, rot, bacteria and rodents;
3) Materials with low moisture absorption, weak water retention, and no corrosion to the pipe wall should be used. A protective layer should be added to the outdoor pipeline insulation layer for waterproofing; 4) Insulation materials should be non-combustible and non-combustible materials. It shall meet the requirements of GB50016 "Code for Fire Protection Design of Buildings"; the insulation of electric heaters must be made of non-combustible materials.
3.6 Heating terminal
The efficiency of the solar system is closely related to the type of collector and the working temperature of the working medium. The heat dissipation components of the solar energy cogeneration system are selected according to the following principles:
1) The solar heating system should give priority to low-temperature radiant heating systems or fan coils; 2) Water-air treatment equipment and radiator systems should use solar collectors with higher efficiency at 60~80℃ working temperature, such as Solar air collector, high-efficiency flat solar collector or heat pipe vacuum tube solar collector. This system is suitable for hot summer and cold winter or mild areas.
3.7 Cooling end
The refrigeration terminal is mainly based on the principles of energy saving, quietness, comfort and beauty, and mainly includes radiant ceilings, fan coil units and other equipment.
3.8 Control system
The control system should adopt intelligent sensing technology to realize unattended, fully automatic control and remote monitoring. 04 The working principle of the solar heating system The solar heating system uses solar energy as the heat source of the heating system, and converts the scattered solar energy into heat energy through the collector to supply buildings for heating in winter and other heating systems throughout the year. The system is mainly composed of solar collectors, heat exchange and storage devices, control systems, other auxiliary heating/heat exchange equipment, pumps or fans, connecting pipes, and terminal heating systems.
The working principle of solar heating system is shown in Figure 2.
In winter, the hot water heated by the solar collectors enters the energy storage device first. When the temperature of the hot water reaches a certain value, the energy storage device directly provides hot water to the floor heating coil or fan coil to achieve heating. purpose. When solar energy is insufficient, auxiliary energy sources can also supplement heat. 05 The working principle of solar absorption chiller. Solar light-to-heat conversion refrigeration, first converts solar energy into heat energy, and then uses heat energy as external compensation to achieve the purpose of cooling. Light-heat conversion realizes refrigeration mainly from the following aspects, namely solar absorption refrigeration, solar adsorption refrigeration, solar dehumidification refrigeration, solar vapor compression refrigeration and solar steam jet refrigeration.
In summer, the hot water heated by the solar collector first enters the energy storage device. When the temperature of the hot water reaches a certain value, the energy storage device provides heat medium water to the absorption chiller, and the heat medium water drives the absorption chiller to operate. Refrigeration cycle. In the absorption chiller generator, the low-temperature heat-medium water cooled by the absorption of heat energy flows back to the energy storage device, and is reheated into high-temperature heat-medium water through the solar collector; at the same time, the refrigerant water generated by the operation of the absorption chiller enters the refrigeration cycle The end of the air conditioner achieves the purpose of air conditioning and refrigeration. When solar energy is insufficient, auxiliary energy sources can supplement heat. The working principle of the solar refrigeration system is shown in Figure
According to the temperature of solar hot water output, the unit operation is divided into two modes: solar hot water alone driving and solar hot water + gas supplementary combustion driving. 06 The working principle of solar hot water system. Solar hot water system is a device that uses solar collectors to collect solar radiation energy to heat water. It is currently the most economical, technologically mature and commercialized in the development of solar thermal energy applications. An application product of. The classification of solar water heating systems can be divided into three types based on heating circulation methods: natural circulation solar water heating systems, forced circulation solar water heating systems, and direct current solar water heating systems.
The solar water heating system is composed of five parts: solar collector, pipeline circulation system, water storage tank, automatic control system and auxiliary heating system. The working principle of solar water heating system is shown in Figure 4.
As a renewable clean energy, solar energy has unparalleled advantages over other energy sources. And the supply of solar energy throughout the year is in good agreement with the demand for heating, cooling and hot water in buildings. 07 Summary Traditional solar energy only provides heating or domestic hot water, but it cannot solve problems such as cooling
okmarts.com integrates diversified systems for solar heating, cooling, and hot water. This is a cross-border technological innovation and integration for the solar thermal utilization industry, which will push the entire solar thermal utilization industry away from the initial stage of hot water utilization. Towards the direction of sustainable development of all-round energy applications.
