A Quantitive Methodology To Analysis Discrepancies Of Energy Use In Office Buildings And Its Applications

Energy conservation of office buildings is one of the most important issues in thefield of Building Energy Conservation in China. As is shown in survey results,significant discrepancies are always found in the energy consumption (EC for short) ofair-conditioning systems among different office buildings, indicating potential of energysaving. By digging into the reasons of discrepancies of energy consumption, it becomespossible to figure out the causes of high EC of air-conditioning system. However, thereare a variety of influencing factors, which indeed interact with each other, making itvery complicated to dissect the discrepancies.In order to analyze the discrepanciesscientifically, a universal methodology is proposed in this paper to quantify thecontribution of each influencing factor and their interaction to the discrepancies of ECof air-conditioning system.The achievements and conclusions are as follows:1. A methodology to quantify the contribution of influencing factors to energydiscrepancies is proposed. It can be used to figure out the main causes ofdiscrepanciesof energy consumption, providing the basis for further energyconservation.The method also has some restrictions such as limited conditions and largecalculation amount.2. Site survey is conducted in three case buildings, namely Beijing A, Hong KongB and America C. Using the survey results as input parameters, energy simulationmodels of these case buildings are developed. By comparing simulated results withmeasured data, the models are validated with the criteria from ASHRAE14. Thequantifying methodology is utilized to analyze the discrepancies of AC systems amongthe three case buildings.3. Based on the energy simulation models of Beijing A and America C and sitesurvey results of VRF systems, it is concluded from simulation results that it is due tothe flexibility of usage mode of VRF system that VRF system is applicable in China. Bythe quantitive methodology, the reasons are well explained: the occupants in Beijing Acan make full use of the individual and flexible control of VRF system so that operatingtime and total cooling load are reduced. Meanwhile in America C, control mode remains the same as centralized water-cooling system, so the cooling load is the same.What’s more, VRF doesn’t have advantage in its system efficient.4. The application of the quantitive methodology in Energy ManagementContract is discussed. The energy saving amount caused by energy conservationmethods can be reasonably separated from total energy change by using thismethod.