Research On Adaptive Conditions And Configuration Of Distributed Energy System

Environment problems caused by low energy utilization ratio and the slather using of fossil fuels has seriously restricted Chinese economy development. Taking energy saving as its starting point, distributed energy system (DES) builds generation system on the end users, founding on the cascaded utilization of energy, which can satisfy users’demands of cooling, heating and power load. Comprehensive utilization of energy of different temperature based on the principle of matched temperature would increase the primary energy ratio. Compared with traditional concentrated and large-scaled energy system, DES has greatly reduced the loss of system transportation because of building on the end of users. CCHP, as the typical representative of DES, usually develops on the basis of cogeneration, which uses high-graded heat produced by fuel combustion to generate electricity and low-grade flue from power generation for heating and cooling, or providing domestic hot water for users.Although the development of DES started late in our country, along with the increasing coverage of natural gas pipeline network, distributed energy station is also developed from place to place. But not all of these power stations realize the energy saving principle, even some of them have already stopped running for a long period of low-load operation or low operation efficiency. In this paper, based on the Jinan area meteorological conditions, DES can be divided into building system and regional system according to construction scale, then calculating and analyzing of the change of the load and its stability of different types of buildings in each season; This paper puts forward the range of heat-electricity ratio when the system’energy-saving maximizes thorough calculating the impact of the size of heat-electricity ratio on the degree of energy-saving of DES. This paper also introduces the performance characteristics and the thermal characteristics of co-generation system’key equipments and common system scenario and analyzes the system efficiency and operation mode. Mainly includes the following aspects:(1) Followed by analysis of different types of building’s load demand, calculation of different buildings’hourly load and the corresponding heat-electricity ratio of typical days in every season, combined with calculation of the standard deviation and variance of each building’s heat and electricity load, this paper can draw a conclusion that public constructions’ electricity load stability is best while hospitals and office buildings’electrical load stability is bad and the industrial parks’electricity load stability in transition season is also not well. And university campuses and public buildings’heat load stability is well, while hospitals、shopping malls and office buildings’heat load stability is bad.(2) By calculating and analyzing the relationship of heat-electricity ratio and total efficiency、energy saving rate; this paper can conclude that when the power generation efficiency is respectively20%,30%and40%:energy saving effect of the system in the heating season is respectively θ>2.7, energy-saving; θ>1.2, energy-saving; completely energy-saving. It is during cooling season is respectively non energy-saving; θ>2.7, energy-saving; completely energy-saving.(3) Analysis of adaptability of DES indicates that hospitals and industrial parks are suitable for running CCHP all the year round; shopping malls are not suitable for using DES; university campuses and office buildings is not suitable for using DES in transition season, while in winter and summer, they need to choose the power unit whose power generation efficiency is more than35%(most time of transition season is during summer and winter vacations, so university campuses doesn’t consider the energy supply in transition season); public constructions are only suitable for adopting DES in heating and cooling season.(4) This paper introduces the performance characteristics of each device of system as well as the common configuration and its principle of co-generation system and establishes a contrast model between CCHP and the corresponding s which combines power acquisition by concentrated power network, gas-fired boilers and electric compression refrigeration. Followed by calculation and analysis of the degree of energy-saving of co-generation system under the conditions of different total efficiency and power generation efficiency, this paper gives the requirements of the power generation efficiency and the system total efficiency during system energy saving and the corresponding operation modes of system under different conditions.