Research And Development On The Prototype Of Domestic Wastewater Resource Utilization

Nowadays,energy and environment have become the theme of the times.How to create safe,healthy and comfortable architectural space environment at the minimum cost of resources,energy and environment is a key problem.In response to this problem,predecessors have carried out a lot of research and development work,and achieved fruitful research results.And a large number of effective energy-saving technologies,key equipments and systems have emerged.However,it is found that there is still much room for improvement in water and energy use patterns and utilization efficiency in current residential buildings from the literature and actual research.Based on the existing energy and water use mode,and the problems of current energy systems in the residential building units,this paper focuses on realizing the recycling of heat energy and cascade utilization of water in residential building units to improve the comprehensive utilization efficiency of the energy in a household.Based on this,this paper takes theoretical analysis and experimental research as the main line,and carries out the following research work:Firstly,a scheme of domestic wastewater resource utilization system was proposed.Taking a family of three numbers with a building area of 120 m~2 in Dalian as an example to aim at maximizing indoor thermal energy recycling and water cascade utilization,a scheme for realizing the recycling of heat energy and water cascade utilization was proposed.The feasibility of the scheme was demonstrated by theoretical analysis,and a concept machine was further proposed.Secondly,a prototype of domestic wastewater resource utilization system was trial-produced,and its performance test platform was designed and built.On the basis of self-developed prototype of domestic wastewater resource utilization system and in order to obtain the operating characteristics of the prototype under nine operating modes of extracting and non-extracting solidification heat,a performance test platform for the prototype was designed and developed,and the system debugging and heat balance checking have been completed.Thirdly,the dynamic performance of the prototype under the condition of non-extracting solidification heat was studied experimentally.The results show that the average of COP_h(under water heating for domestic hot water mode)of heat pump with air,wastewater,and air plus wastewater as heat sources is 3.77,3.28,and 3.97 respectively,and the heat of waste heat recovery is 6.3MJ,14.7MJ,and 10.3MJ respectively,accounting for 39.9%,93.0%,and 65.2%of the total apparent heat of wastewater,respectively;the average of COP_h(under space heating mode)of heat pump with air,wastewater,and air plus wastewater as heat sources is 2.90,2.85,and 3.15 respectively,and the heat of waste heat recovery is 7.9MJ,15.6MJ,and 15.6MJ respectively,accounting for 39.9%,98.7%,and 98.7%of the total apparent heat of wastewater,respectively;the average of COP_c(under space cooling mode)of air-cooled,water-cooled,and air plus water cooing air-conditioning systems is 3.31,3.89,and 3.79 respectively.Domestic wastewater resource utilization system has good energy saving under the mode of water cooling for space cooling and waer heating for domestic hot water.The average of comprehensive COP of the system is 6.11,and the heat of waste heat recovery is 8.2 MJ,which accounts for 86.7%of the total apparent heat of wastewater.Fourthly,the dynamic performance of the prototype under the condition of extracting solidification heat was studied experimentally.The results show that the initial water temperature increases from 8.00 C to 12.50 C,the average of COP_h(under the non-real-time deicing to provide hot water mode)increases from 2.32 to 2.50,and the amount of waste heat recycling decreases from 12.8 MJ to 11.2 MJ and the proportion of the total apparent heat of wastewater decreases from 735%to 238%;the initial water temperature increases from 8.00 C to 12.50 C,the average of COP_h(under the real-time deicing to provide hot water mode)decreases from 3.03 to 2.50,and the amount of waste heat recycling decreases from 4.5 MJ to4.0 MJ and the proportion of the total apparent heat of wastewater decreases from 214%to85%.Finally,the technical and ecomomic analysis of the domestic wastewater resource utilization system was carried out combining with the test results of the prototype.Taking Harbin,Beijing,Shanghai,Guangzhou and Kunming as examples,the comparative analysis results show that the amounts of the annual energy cycle are 17.70 GJ,15.50 GJ,15.13 GJ,13.27 GJ and 9.88 GJ,accounting for 25.31%,25.90%,24.70%,25.18%and 30.90%of the total energy consumption,respectively;the annual water saving is 49 m~3,accounting for 1/3 of the total water consumption;the annual total energy saving of each household in China is1400-5180 kWh,and the life cycle cost of the unit is 1.4-3.1 lower than that of the traditional equipments.When the life cycle cost is lower than that of traditional equipments,the service time of unit is 0.66-0.34 years.The research results of this paper have reference value for the design of a household energy system in a residential building unit and the realization of the recycling of heat energy and cascade utilization of water in a household unit.These research results provide new ideas for solving the core problems in HVAC,and have positive significance for improving the utilization mode of resources and energy in residential buildings,greatly improving the utilization efficiency of resources and energy,and promoting the green development of buildings.