Welding Parts,Welding Fabrication,Welding Assembly,Cnc Machine Parts Dongguan Changsheng Technology Co., Ltd , https://www.dgcsmachining.com
The application of compression heat pump hot water unit in the central hot water system Heat pump hot water unit is the emerging hot water manufacturing equipment in recent years, it is powered by electricity, easy installation, short construction period, covers an area of ​​?? less , Without the need for fuel storage sites, slag-free transportation costs and waste treatment costs, without the need for specialized duty personnel, compressive heat pump water heaters have shown obvious advantages for concentrated water heating systems in urban areas [1]. On the other hand, the heat pump can absorb high-energy, environment-friendly and non-polluting technologies [2] by absorbing natural energy, waste heat, annual heat supply and cooling in summer. Heat pump hot water unit heating power of 300% or more, the same output, heat pump hot water unit input power only electric boiler 1/3 to 1/4, the pressure on the power supply capacity is not large, the cost of producing hot water only Electric boiler 1/3 to 1/4. Heat pump hot water unit can also use the energy storage device, the use of night trough electric system to obtain a certain temperature of hot water, stored in the insulation tank, for peak use, play peak load effect. In recent years, with the improvement of energy saving and environmental protection requirements in our country, heat pump hot water unit has been widely used in central heating water system, especially in the area south of the Yangtze River valley in China, energy saving effect is very significant. 1, Project Overview Shenzhen a hotel has 221 sets of rooms, all day hot water supply hot daily peak at 8 to 11 pm. According to occupancy 300 people, guesthouse guest hot water according to national standard daily 200L / person calculation, about 60t / d hot water, a larger amount. The original design of the roof with four vertical gas boiler, the use of two loop circuit for hot water: two above the 21st floor, high pressure cycle; 21 below two, low pressure cycle. In order to reduce costs, save energy and improve the hotel environment, the hotel decided to transform the central hot water system, the transformation program using 5 Nanjing Huadian Hot Springs Heating Technology Co., Ltd. production of heat pump hot water unit, the transformation of the hotel's original hot water The original supply system remains the same, the original gas boiler as an emergency equipment, gas room for the back to the main water pipe, the original water pipe is still functioning in the new system, the original system for the total back to the supervisor connected to the heat pump hot water Unit for, back to the charge in the middle plus a heat storage tank, to facilitate the reduction of equipment selection capacity. The system also uses automatic control, according to the need to set the water temperature. New equipment layout in the roof, does not affect the appearance, no noise interference. 2. Selection of design parameters (1) Cold water temperature: 17.5 ℃ in summer and 20 ℃ in winter and 15 ℃ in winter (2) Hot water outlet temperature of heat pump unit is 55 ℃ and indoor hot water outlet temperature is 40 ℃ (3) Peak electricity price is 0.8 Yuan / KWh, ice storage price 0.3 yuan / KWh 3, selection of heat pump hot water unit selection according to climatic conditions, the average daily water consumption and water temperature, the user's water temperature into account, select the model. Unit working hours generally take about 70% of the time. As the energy efficiency ratio of the unit is affected by the ambient temperature, the most adverse conditions and the initial investment cost need to be taken into consideration when selecting a model [3]. 1 Winter heat load Qn = 60 × 1000 × 4.187 × (40-15) × (1 + 0.1) = 6908.6MJ = 1919.04KWh (0.10 is the system heat loss coefficient and 15 is the upper water temperature.) 2 Excessive quarter-heat load Qn = 60 × 1000 × 4.187 × (40-17.5) × (1 + 0.1) = 6217.7MJ = 1727.13KWh 3 summer heat load Qn = 60 × 1000 × 4.187 × (40-20) × (1 + 0.1) = 5526.8 MJ = 1535.23KWh Table 1 Energy efficiency ratio of heat pump hot water unit Ambient temperature ℃ Input power KW Output power KW Energy efficiency Cop -5 7.0 15.6 2.23 0 7.4 17.5 2.36 5 7.9 20.2 2.56 10 8.3 23.2 2.80 15 8.8 26.9 3.10 20 9.4 31.5 3.35 25 10.2 38.1 3.74 30 10.8 43.6 4.04 35 11.4 48.6 4.26 40 12.3 52.5 4.27 Table 2 Main technical performance parameters of heat pump hot water unit Type Project Name Unit Value Unit technical performance parameters Item Hot water outlet temperature ℃ 55 Rated heating capacity KW 26.9 Rated hour heating Water L / h 600 Rated input power KW 8.8 Maximum input power KW 12.3 Installation conditions Water Dimensions mm 1290 × 960 × 1150 Net weight Kg 350 Rated water pressure MPa 0.6 Maximum water pressure MPa 1.0 Pipe diameter DN40 Operating conditions Electrical voltage V 3 ~ / 380 ± 1 0% Frequency of use Hz 50 Maximum current A 28 Grounding requirements Ω <10 Temperature Ambient temperature range ℃ -5 ~ 40 Under rated conditions, the parameters are as follows: <Q / 3201HDRQ-01-2002>, cold water 18 ℃, hot water 55 ℃, Dry bulb temperature 55 ℃, wet bulb temperature 12 ℃ According to the winter heat load and unit performance parameters, at an ambient temperature of 7 ℃, 1 HAM096 heat pump water heater output power 21.4kw, 5 total output power of 107kw, every day 18 hours of operation to meet the heat load needs. 4. Economic analysis (1) Thermal efficiency and heat value of heat source Table 3 Heat source heat value table Heat source heat value Thermal efficiency,% Actual heat value Gas boiler 26000kcal / m3 65 16900 Heat pump 860kcal / kwh 350 3010 (2) Two ways The cost of heating 1 tonne of water costs 1000 kilograms (1 ton) of cold water of 15 degrees, hot water heated to 40 degrees, 25,000 calories of heat, for example, the cost of the two heat sources. (1000 × 25 = 25000 kcal). Table 4 Fee Schedule Heat source Power Consumption Unit price Cost Gas boiler 1.48m3 13 yuan / m3 19.24 yuan Heat pump (peak price) 8.31kwh 0.8 yuan / kwh 6.65 yuan Heat pump (trough price) 8.31kwh 0.3 yuan / kwh 2.49 yuan Note: Is your hotel to provide 13 yuan / cubic meter count. (3) Calculation of costs Calculated on the basis of winter heat load, heat pump hot water system is used for supplying hot water, using trough electricity for 8 hours a day, producing 27 tons of hot water and electricity cost of 67.23 yuan per day, using peak electricity for 10 hours per day Hot water is 33t, electricity is 219.45 yuan, a total of 286.68 yuan. And the hotel originally used gas boiler heating water costs 1154.4 yuan a day. After the renovation of the hotel can save running costs of 867.72 yuan a day, saving operating costs more than 310,000 yuan each year. (4) Heat pump and gas boiler daily operation and maintenance costs compared Heat pump The reason why this new energy-saving products can be quickly used in central water heating system is widely used, mainly because of its energy saving, environmental protection, safety and comfort Many advantages by more and more users of all ages. Its daily maintenance costs are also lower than the conventional hot water system, mainly in the following aspects. 1 heat pump hot water unit by the hot water tank, you can always use hot water, without someone switch machine and maintenance. Saving a boilerman costs more than a gas boiler. 2 heat pump hot water unit maintenance include: the machine shell, evaporator heat sink cleaning. Mainly to clean the evaporator heat sink dust, gas boilers to gas as a fuel, are flammable, explosive dangerous goods, with insecurity. 3 heat pump hot water unit can be placed in outdoor roof and other places, does not affect the work efficiency. The gas boiler regularly by the technology, safety supervision and inspection, accreditation. 4 heat pump hot water unit using electric energy to clean the air, will not cause air pollution. Gas boiler gas combustion, the flue gas emissions still contain sulfur dioxide, nitrogen oxides, carbon monoxide and other harmful gases, long-term emissions, will pollute the surrounding environment. 5 heat pump hot water unit using parallel operation of units, respectively, separate control, if one of the failure, does not affect the normal operation of other units. 6 heat pump hot water unit life of up to 15 years, converted, lower than the cost of using gas boilers. 5 Conclusion Through the above analysis, we can further recognize the heat pump hot water unit in the application of the central hot water system prospects. After the project was put into operation, the investment cost of the equipment was recovered within one year and was praised by the owners. As a result of the hotel in the life cycle of the heat pump water heater can save costs more than 470 million, energy saving effect is very obvious. Heat pump hot water unit of this new energy-saving products will become the first choice of China's central hot water system. References [1] Jiang Nengzhao, editor. Air-conditioning heat pump technology and its application. [J] Beijing: Mechanical Industry Press, 1997 2 Jiang Yiqiang. Air source heat pump chiller selection [J]. HVAC, 2003,33 ): 30-33 3 Nanjing Huadian Hot Springs Heating Technology Co., Ltd. Electrician heat pump hot water unit technical manual, 2003 Author brief introduction Liu Jun, male, born in 1976, Shaanxi Pucheng people, graduated from Baotou Steel Institute heating ventilation and air conditioning Engineering, bachelor's degree, assistant engineer, is mainly engaged in heat network design, heat pump heating and energy saving work.