Abstract: The sewage heat pump project of Tanzhou Sewage Treatment Plant in Miyun County introduces the advanced technology and equipment from northern Europe and adopts the urban water source without any treatment as the water source heat pump technology, which transforms the low-level energy in the wastewater through the heat exchanger and heat pump unit Become a high energy heating, cooling, supply hot water. Scope Mounts,Red Dot Riser Mount,Mounts Riser Sight,Tactical Red Dot Sight Mount Guangzhou Miaozhun Jie Trade Co.,Ltd. , https://www.focuhunter.shop
Keywords: Sewage heat exchanger Heat pump economy
First, the project overview:
Miyun County Tanzhou sewage treatment plant is located in the beautiful Chaobai River, Miyun county is the only centralized sewage treatment points, daily commitment Miyun county nearly 24000m3 of sewage treatment. Sewage quality is stable, perennial temperature at 13oC-15oC. The factory has about 10000m2 buildings (office buildings, factories, garages, etc.), the use of untreated urban sewage as a heat source for the factory heating and partial cooling (only the office needs refrigeration), and also for domestic hot water use. It uses sewage as a heat source when heating, and uses sewage as a heat sink when cooling. Due to adequate sewage treatment plant sewage supply, extraction and emission of heat to meet the needs of heating and cooling.
The project is Miyun County Tanzhou sewage treatment plant coal-fired boiler room renovation project. As the original coal-fired boilers cause some atmospheric pollution each year, in order to meet the demand of environmental protection in Beijing, the heating system has been decided to renovate the heating system and no longer use coal. Therefore, both the heat-supply water and the cold water Source heat pump system. Sewage treatment plant transformation is divided into two parts, part of the transformation of office buildings, the other part is the transformation of plant equipment, office buildings are installed to the cooling fan heat pipe, the installation of equipment plant is better thermal performance Steel string radiator.
Second, the system principle and design
In winter, the temperature of the sewage is about 12-15 ℃, and the temperature of the effluent is about 7-10 ℃ after heat exchanger. The heat in the sewage is extracted by the system as the low-temperature heat source of the water source heat pump unit and enters the evaporator of the heat pump unit. Circulating water heating system, supply and return water temperature is 50-45 ℃. In summer, the sewage temperature is about 14-18 ℃ after the heat exchanger heat exchanger discharge temperature of 19-23 ℃, sewage away the heat in the system as a water source heat pump cooling water, heat pump evaporator water as a cooling System circulating water, water supply and return temperature of 7-12 ℃. The heat pump has a heat recovery function to ensure the supply of domestic hot water while operating in winter and summer.
User-side water supply separately through the manifold to each monomer floor. System winter, summer conditions by switching the station system to achieve the valve system.
system design:
1, heating and air conditioning design parameters:
Winter outdoor air-conditioning temperature -12 ℃
Winter interior design temperature 18-24 ℃
Summer outdoor air-conditioning calculation temperature: 33.2 ℃; wet bulb temperature: 27.3 ℃
Summer indoor air conditioning design temperature 22-26 ℃
2, load calculation:
Estimate the heating index of comprehensive building 60w / m2
The total design of heating and cooling area of ​​10000m2, the actual heating area of ​​6000m2
The total design heating heat load:
10000 × 60w = 600kw
The total cooling load to 70% of building cooling to 80w / m2 calculation
7000 × 80w = 560kw
3, the required hot and cold conditions:
Winter water requirements: 80t / h, the temperature difference is 5 ℃.
Summer water requirements: 120t / h, the temperature difference is 5 ℃.
Because the sewage plant flow of 1000t / h, much larger than the design of water demand.
Third, the project focus and difficulty
1, sewage heat exchanger
The use of untreated sewage as a source of water for heating and cooling, water source heat pump is a way, due to suspended solids in the sewage, dirt and sediment more, and the greater the pH of the sewage, easy to corrosion of the heat exchanger, scaling , Clogging and other phenomena, thus seriously affecting the heat transfer efficiency. Through experimental tests, the kinetic viscosity (15 ℃) of urban primary wastewater is about 40 times higher than that of clear water (15 ℃, 1.14 × 10-6? / S), that is, 4.56 × 10-5? / S. Such a high viscosity, corrosive and suspended material on the heat exchanger material, surface roughness and internal structural design have put forward high requirements. According to the investigation of the domestic heat exchanger industry, at present, there are few heat exchangers in China which can meet such harsh working conditions and are suitable for the price. Therefore, the Nordic relevant expert group which is ultimately involved in the project, Time study to determine the material of the sewage heat exchanger, using a variety of new materials and surface treatment technology to solve the problems of corrosion, clogging and scaling. The heat exchanger components purchased in Finland, Sweden, Denmark and other countries, and ultimately assembled by molding in Malaysia.
Since the project was in operation for three years, the heat exchanger did not show any corrosion, clogging and fouling phenomena, which basically met the needs of the normal operation of the sewage heat pump system and proved that this heat exchanger was suitable for the wastewater quality in China.
2, grille
Before entering the sedimentation tank, the sewage passes through a coarse grid to intercept the floating particles and suspended solids of the larger particles in the sewage, and the intercepted grid residue is manually removed. Sewage from the sedimentation tank and then through a fine grid to intercept small particles of sewage floating objects and suspended solids, intercepted grid slag about half an hour automatically transferred to the garbage pond. After two grilles filter, the size of the particles in the sewage float and suspended solids have been basically blocked, and then enter the sewage heat exchanger, so you can avoid heat exchanger clogging.
Fourth, the measured data analysis
The water source heat pump system from January 10, 2003 into operation, after experiencing the coldest winter in Beijing in recent years, fully tested the performance of sewage source heat pump units. The unit is in good working condition in summer.
In order to more accurately analyze the economy of the sewage source heat pump, we arranged full-time staff to continuously record the equipment for more than two months and record the data every two hours, including the number of meters, temperature and pressure.
According to the finishing record data, the statistics of the data from February 6, 2004 to February 26, 2004, for 20 days in succession, can obtain the following data:
Sewage temperature: 11-17 ℃
Evaporator inlet temperature: 10-16 ℃
Evaporator outlet temperature: 6.5-14 ℃
Condenser inlet temperature: 37.5-44 ℃
Condenser outlet temperature: 40-46.9 ℃
Domestic hot water temperature: 50-55 ℃
February 6, 2004 The meter shows the number: 992
February 26, 2004 The meter shows the number: 1445
Note: AC transformers are 1: 100
The total electricity consumption is: (1445-992) * 100 = 45300kwh
The average COP of the 20-day system is: 6000 * 60W / 94.375 = 3.81
According to the electricity price of 0.5 yuan / kwh calculation, the cost of 45300 * 0.5 = 22650 yuan
The average daily heating costs 1132.5 yuan / day.
February 6 to February 26 is a very cold period, calculated by heating season 120 days, the cost of the entire heating season should be multiplied by a factor of 0.6:
1132.5 * 120 * 0.6 / 6000 = 13.59 yuan / m2 (including domestic hot water)
Compared with other heating methods, sewage source heat pump system running costs lower, with obvious economic significance.
Fifth, the project advantages:
Environmental protection
Sewage source heat pump is the use of raw sewage as a source of cold and heat, energy conversion heating air conditioning system. The heating system eliminates the need for coal, gas, oil and other boiler room system, there is no combustion process to reduce greenhouse gas emissions of CO2 and other air pollutants; cooling for the cooling water tower was omitted to avoid the cooling tower noise and mold Pollution. Do not produce any waste, waste water, waste gas and dust, make the environment more beautiful.
Energy saving
Sewage heat pump available sewage temperature in winter is 11-15 ℃, the sewage temperature is higher than the ambient air temperature is a good low temperature heat source; summer sewage temperature is 17-21 ℃, the sewage temperature is lower than the ambient air temperature is better The cooling body. This temperature characteristic allows the sewage heat pump to operate 20% more efficiently than conventional air conditioning systems.
3. Festival funding
The system also integrates heating, air-conditioning and domestic hot water supply. - Set of heat pump system can replace the original heating boilers, refrigeration and air conditioning and hot water heating three sets of devices or systems, thereby increasing the economy.
Stable
Sewage temperature is relatively stable, the scope of its fluctuations is much smaller than the air changes. Is a good heat pump heat source and air conditioning cold source, sewage temperature is more constant characteristics, making the heat pump operation more reliable and stable, but also to ensure the system's high efficiency and economy. There is no air source heat pump in winter defrost and other difficult issues.
5. High degree of self-control
According to the characteristics of the system, we choose four compressor units, the system automatically select the compressor start and stop according to load fluctuations, improve system operation efficiency; high degree of automatic control, the operation process without special duties; management is relatively easy, unit maintenance costs Low; life of up to 15 years.
VI Conclusion
1, sewage - water source heat pump thermostat system has the characteristics of water, energy saving, environmental protection, is the use of urban sewage heating, cooling new situation of air conditioning, in line with the world's urban wastewater reuse and urban water problems. The adoption of this technology in Miyun County is of great significance for promoting the smoke-free counties and green eco-friendly counties in Miyun.
2, the use of untreated urban sewage as the source water source heat pump system in Miyun County, Tanzhou sewage treatment plant application success, marking the application of sewage source heat pump technology in our country another great development.
September 19, 2023