Comparison of the completeness of the climate probability-statistic model and the reference year model

Abstract

Evaluation of the building energy efficiency, which has been admitted as a criterion of the energy safety, provision shall be made of determination of the energy consumption by the heat microclimate maintenance systems in the rooms. It can be be calculated only according to the data of the probability of the outdoor climate distribution in the construction region. The model correspondence to its design technological processes is an important aspect. That is why there is a vital question of how to provide the completeness of information using different climatic models for calculation of the processes, which occur differently in time. This work is aimed at comparing the completeness of all the possible combinations of temperature and relative humidity, as well as their repeatability in different climatic models. On the one hand, each particular model of the climate should more fully describe the possible weather situation of the construction area, affecting the calculation result. On the other hand, the model should not be limited by any restrictions of extra "qualities" and the climatic parameters that are not used in a particular task. Currently, the reference year climate model, which is presented in the European standard ISO 15927-4:2005, is the most widely used in the world. This model is the most appropriate for calculations of transient processes of the thermally resistant objects. However, the determination of the annual energy consumption by air conditioning systems with instantaneous processing outdoor air, is more consistent with the probabilistic-statistical model of climate. It represents a table with the cells containing the frequency of occurrence of temperature and relative humidity spaced at 1 °C of temperature and 5 % of relative humidity. The article compares the completeness of information, which is provided by each model and calculated on the basis of each of two models of heat, cold and water consumption by air conditioning plants. The comparison has been made for installations of the inlet air supply processing according to the schemes of cocurrent flow with secondarypreheating and cocurrent flow with by-pass (direction of a part of the air in the bypass of the spraying chamber). The results of the comparison of the probabilistic field of combinations of the outdoor air temperature and the relative humidity of the two models confirm the higher completeness and accuracy of the probabilistic-statistical model in the description of heat and humidity status of the outdoor air of several years. The calculations showed that the energy consumption by air conditioning systems, which has been obtained on the basis of two climate models, differ from each other in 3.8 % of warmth, 1.6 % of water, 53.8 % of cold and electricity. The results confirmed, that during the calculations of the cold consumption, the distortion in the distribution of the enthalpy of the outside air, which depends on the distribution of temperature and relative humidity during the cooling period, leads to significant errors.