Views:1 Author:Site Editor Publish Time: 2019-06-16 Origin:Site
With the country's constant attention to energy conservation, emission reduction and air pollution control, clean energy heating has become a trend in the north and even the whole country. "Coal to clean energy" has been staged in various places, becoming the most lively and highest hit rate in today's energy field. Solar heating is an important part of clean heating. With the increasing emphasis on solar heating in Beijing, solar heating is expected to radiate to the entire northern region. However, current solar heating still faces many problems in China. This section of the paradigm will combine some of the cases and expert opinions to further explore the breakthrough strategy of solar thermal enterprises.
Sun Rain: Jinjiayuan Community, Changzhi City, Shanxi Province
It covers an area of 21,384 square meters and a building area of 57,000 square meters. The geographical coordinates of Changzhi County are 111°58′03′′～112°44′04′′ east longitude, 35°49′～ 37°08′ north latitude, the average altitude is 1000 meters, the annual sunshine hours are 2310～2660 hours, the average exposure The amount is 4200 ~ 5400MJ / m2. It is planned to use a full glass vacuum tube horizontally arranged header collector, which requires a heat collection area of 4,237 m2. The project uses a solar rain 240 tube/group of collectors 90 sets (3 rows, 30 rows per row), 200 tubes/group. The collectors 19 groups (one line, 19 rows each), a total of 25,400 vacuum heat pipes, a total of 4,254 m2. The heat exchange device adopts the way of heat exchange well, the heat exchange well is 600, the depth of the well is 100m, the heat exchange area of each well is 20.25 square meters, and the total heat exchange area is 12150 square meters. The collector is installed on the building surface to achieve a combination with the building.
Due to the limitation of solar energy distribution and seasonal mismatch, the utilization of solar energy is limited. The combination of solar energy and ground source heat pump compensates for the instability and intermittent characteristics of solar energy, and reduces the area of solar collectors and buried heat exchange. The combined operation can meet certain heating requirements. The project uses solar energy resources stored in the shallow soil of the earth as a heat pump heat source and air conditioning cold source through a ground source heat pump. The system can be divided into two systems: solar collector heat storage cycle and soil heat storage and heat cycle. The system consists of ground source heat pump, solar collector, hot water storage tank, connecting pipeline and control system.
In the winter, the liquid in the pipeline extracts the heat from the underground and then is introduced into the building through the system. Due to the low temperature of the soil in winter, the temperature of the soil around the buried heat exchanger is not effectively recovered in the early stage of the system operation, and the heat pump efficiency is also reduced. Therefore, solar energy is used for seasonal soil heat storage, and the solar heat collected in addition to the winter is stored in the soil through the buried heat exchanger. In the winter, the heat is taken out by the heat pump to remove heat from the soil, and the heat is stored. Cooling capacity for summer use. In the summer, heat is extracted from the building and discharged into the ground through the system, while storing heat for winter use. The system converts solar energy into hot water, stores the hot water in the water tank, and then supplies it to the heating end (fan coil radiator heating and cooling) through hot water to provide building heating, cooling and domestic hot water.
The project is an active solar heating system—liquid working fluid collector short-term thermal storage heating system. The main project site is located in Shuanghu County, Tibet, which provides winter heating and bathing hot water for the Pulugangri Hotel.
According to meteorological data, the local elevation is about 4,950m, the annual average solar radiation is about 21MJ/d, the sunny day is over 95%, and the outdoor outdoor temperature is about -25°C.
The hotel is a two-story building with a total construction area of about 2,000 m2. The building area required for heating is 1,350 , including 600 for rooms, 230 for kitchens and restaurants, 115 for conference rooms, 65 for bathrooms and laundry rooms, halls and warehouses, etc. About 340.
The hotel has good enclosure structure and good thermal insulation performance; the roof of the hotel is flat, the main body is oriented in the south direction, and the lighting conditions are good. It is suitable for installing solar collectors. The available area of the hotel roof is about 750(the other There are different areas with elevations of about 100 on both sides of the east and west. The original building has a separate water tank with an area of about 60, which can be used to store solar water storage tanks and other equipment.
The system takes into account the seasonality of heating, so the design principles determined are:
During the heating period, the solar heating system is mainly used for heating the hotel room or for showering. In the non-heating period, the solar heating system is used to provide shower hot water for the hotel and supply a large amount of production and life. With hot water, the solar system can make its due contribution during the non-heating period, so that the whole year can be comprehensively utilized, so that the whole system can generate greater economic benefits.
The system is mainly used to provide heating for the building room during the heating period (can be used for showers). The water supply temperature is 65 °C ~ 80 °C, the return water temperature is 50 °C ~ 65 °C, and the return water temperature difference is about 15 °C. In the non-heating period, it is used to provide shower hot water for hotels. The domestic hot water tank adopts the highest temperature limit, and the temperature limit is 85 °C to ensure the normal operation and service life of the whole system. The system has been running well for several years.
The solar heating system built by the Pulugang Hotel in Tibet involves various aspects of system design and system operation, and has gained rich practical experience to further design various types of solar heating systems for the future, and for the severe cold in China. The cold area promotes the establishment of green buildings and provides a relatively solid technical foundation.
Tengzhou City, Shandong Province is located in the southern part of Shandong Province. It is located in a warm and semi-humid area with abundant sunshine and an average annual sunshine of 2383 hours. The annual average temperature is 13.6 °C, the hottest month is July, and the average temperature is 26.9 °C. It is very suitable for solar heat pump heating and heating. Construction conditions of the project. Located in Tengzhou Economic Development Zone, Shandong Guangpu is a high-tech private enterprise specializing in the research, development, production and marketing of solar thermal utilization products. Taking into account the local climatic conditions, environmental protection requirements, fuel structure, energy efficiency and economic endurance, the company has built a solar heat pump heating and heating project on the roof of the company's office building. The heating is “energy-saving, efficient and stable. Reliable" is a technical feature. The combination of solar energy and air source heat pump for heating and heating further improves energy utilization, reduces the restriction conditions of the heat pump hot water system, and maximizes the overall operation of the system. The system controller uses Delta's programmable controller as the core controller. The PLC controls the operation of the system, the fault of the detection system, and the operation of various parts of the drive system through parameters such as temperature, pressure, flow, and liquid level. Remote monitoring is possible with the help of computer software. In the project example, the low-carbon energy-saving, high-efficiency and multi-complementary heating system provides safe and comfortable domestic hot water for the employees of the company, and provides heating heat for the company office building.
The solar heat pump is a device that combines an air source heat pump and a solar heat collecting system. When there is solar radiation, the system converts into a solar heat pump principle to heat the system; when there is no solar radiation in the rainy or night, the system is converted into an air source heat pump. The principle of heating. The system device not only ensures the stability of heating, but also has higher heating efficiency than the air source heat pump and the solar collector system. The energy saving effect is remarkable through the testing and application of the solar and heat pump heating and heating engineering on the roof of the office building.
The working principle of the solar energy and heat pump heating engineering project: using the principle of Carnot cycle, the solar collector is made into a solar energy and air source collector evaporator, and the refrigerant working medium in the collector evaporator directly absorbs solar radiation energy ( There are conditions of solar radiation) and air heat (at night or rainy days) low temperature evaporation, compressed by compressor to discharge high temperature and high pressure refrigerant vapor into high temperature condenser condensation heat release, condensate in high and low pressure difference Under the thermal expansion valve, the pressure is reduced and the temperature is lowered into the evaporator to absorb heat and evaporate, thereby forming a heat pump working cycle. The system realizes a small amount of electric energy, and transfers a large amount of heat energy from a low-temperature heat source to a high-temperature heat source. The heat transferred is divided by the energy consumed by the heat pump (COP).
1. On-site monitoring technology:
The project uses solar collectors to absorb solar energy as the main heat source, and the air source heat pump as the auxiliary heat source, which greatly reduces the local illumination restrictions of the ordinary heat pump hot water system, and uses PLC as the controller through the computer. Communication with system controllers and other devices enables on-site real-time simulation, fault monitoring and diagnostics, as well as remote communication, remote control and fault handling.
2. Intelligent control technology:
The system adopts intelligent microcomputer automatic control technology, which can automatically reach the set water temperature and automatically replenish water to ensure the output water pressure is constant. The water supply temperature is adjustable from 45 °C to 60 °C.
3. For civil commercial use:
The system has a high water output rate, and there is high temperature hot water after 10S. It has a large amount of water, and is especially suitable for use in civil bathing centers such as schools, hotels, hospitals, etc. It can also provide commercial hot water for hot water in textile, chemical, light industry and other industries.
4. It is not affected by the weather, and it can be used in both sunny and sunny days.
It uses solar energy for heating on sunny days. When the rain and daylight intensity are poor, the dual heat pump heating system is used. The average thermal efficiency of the system is up to COP=4.5.
5. Flexible installation:
Collector system and heat pump units can be installed on the roof can also be placed in the ground.
6. Efficient and economical, green:
Unit 20 hours water production of 12 tons investment offer about 12 million, the average hot water system investment 10,000 yuan / ton, the payback period is 18 months. Green, environmentally friendly hot water system.
Solar heat pump refers to the combination of solar collector technology and heat pump technology, using solar energy as the main heat source of the evaporator, other low-quality energy as auxiliary energy, heating system that synergizes with solar heat source after heat pump technology improves quality, solar energy The heat pump can simultaneously improve the efficiency of the solar collector and the performance of the heat pump system.
The solar energy and heat pump of the 500m2 office building in the company's 500m2 office building are combined with solar energy and air energy heat pump to ensure the whole year's total climate heating. In the actual operation process, the energy saving effect is remarkable, and the environmental protection and emission reduction effects are also Very good, providing domestic hot water for the whole factory staff and providing heating source for the office building. Solar and air source heat pump integrated heating system solution is a new trend in the development of central hot water system heat source equipment in recent years, and the integration of solar energy and heat pump has two modes of consideration: one is based on solar heating, and the air source heat pump is heated. Auxiliary, but the premise is that the building allows the placement of solar collector panels, which has sufficient area; the second is the air-heat pump heating, supplemented by solar heating, the company's office building just meets the installation conditions. The operation mode of the heating project is to enable the air source heat pump to operate efficiently, stably and reliably in a low temperature environment, using solar energy as its auxiliary heat source or directly heating the water in the water tank or providing preheating.
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