Search

Abstract: Although variable-air-volume system (VAVS) can save much energy compared with other kind of HVAC system (e.g. constant-air-volume system (CAVS), fan-coil system (FCS)), it demands more investment. The rate of return of variable-air-volume system, which is closely related to the energy-saving rate of the system, ought to be taken into account by the engineers in the course of design. China has a wide territory and different climates that will impact on the energy-saving rate of variable-air-volume system. To help the engineers have a good idea of the rate of return of variable-air-volume system in different areas of China, it is necessary to establish such program that can evaluate the energy-saving rate of variable-air-volume system compared to constant-air-volume system and fan-coil system. In this paper, the specific energy models of the primary equipments in HVAC system are established, and the evaluation program for the energy-saving of variable-air-volume system compared to constant-air-volume system and fan-coil system are expounded. The parameters in the energy models, which may impact the validity of the evaluation program, can be obtained from the field-testing data or the performance data provided by the product manual. One small office building is taken as an example, the year-round energy simulations of the three kinds of HVAC systems (variable-air-volume system, constant-air-volume system and fan-coil system) of the same building have been made, and the energy-saving of the variable-air-volume system has been evaluated in six cities of China by the program. The evaluation program can also be used to analyze the energy-saving of variable-air-volume system in medium and big office buildings. [Copyright &y& Elsevier]

Indoor thermal environment design parameters have a significant impact on human thermal comfort, health and building energy consumption. The methods of determining indoor thermal environment design parameters in China and around the world are mainly based on the PMV model. This method often results in certain errors deviations from the actual situation and has difficulty reflecting the differences in the thermal environmental requirements in different climate regions, seasons, building types, etc. This paper proposes a data-driven method based on Chinese Thermal Comfort Database and uses a logistic regression to obtain the indoor air temperature range that 80% of occupants find thermally acceptable under different conditions. The results indicate that the prediction of this model are in good agreement with the actual data and have as higher accuracy in predicting the percentage of thermal acceptability than a linear regression method. This model shows that different regions, seasons, and building types have different acceptable temperature ranges and that the acceptable air temperature ranges are on average 2.0 °C wider than the ISO 7730 and 0.7 °C wider than the GB50736-2012. This method is conducive to the determination of air temperature thresholds and better reflects people's equirements for thermal environment under different conditions. [ABSTRACT FROM AUTHOR]