Search

Abstract Due to high power consumption and air pollution situation in China, insufficient indoor fresh air during heating season can be a noteworthy problem. Unlike previous researches, which mainly focused on cooling capacity of Earth-air Heat Exchanger (EAHE), feasibility of EAHE combined with Heat Recovery Unit (HRU) as an independent heat source to heat cold air in severe cold regions was firstly verified. U-shaped buried pipes were proposed to enhance heat transfer as well as save land-use. Thorough measurements of air and soil parameters and power consumption were conducted under several operation modes, performance indexes like heating capacity, heat transfer efficiency and COP were analyzed. Results showed average temperature rise of 14.0 °C provided by EAHE and further 12.1 °C promotion brought by HRU helped outdoor air reach to an acceptable level without auxiliary heating equipment. Heating capacity of EAHE increased with decreasing inlet temperature, when inlet temperature changed from −0.4 to −24.4 °C, heating capacity increased from 709 W (19.7 W/m) to 7718 W (214.4 W/m). Performance of HRU rarely reacted to climatic conditions because of the stable outlet temperature of EAHE. Maximum comprehensive COP was 16.3, which indicated the high efficiency of system. Results showed EAHE can be expanded to severe cold regions and achieve good efficiency. Highlights • Feasibility of applying Earth-air Heat Exchanger in severe cold regions was firstly investigated. • Experiments were conducted during heating season to evaluate the performance of system. • Correlation between heating capacity of EAHE and inlet air temperature was strong. • The proposed system can effectively heat fresh air without auxiliary heating equipment. • The influence to indoor environment brought by proposed system can be ignorable. [ABSTRACT FROM AUTHOR]

The aim of the study was to develop models for energy planning for an air supported sports hall by analyzing different energy efficiency possibilities. This is a very specific building type suitable for sport activities in cold climates. The observed hall was operated when outdoor temperature was under 5 °C, while the most common measured indoor air temperature was 8 °C during the year. Neither indoor nor outdoor temperature influenced the overpressure. Based on the measurements, the specific annually heating energy use was 75 kWh/m 2 . The results showed that improvement in the hall insulation would not give a significant effect on the heating use. The analysis of energy efficiency measures showed that air recirculation has the greatest effect on total energy use and the air recirculation could give an energy saving of 27% when 50% of the indoor air was recirculated. The results might be used to calculate heating energy demand for different operation scenarios in the air supported halls. The results give a simple tool to size the heating coil in the AHU and for energy planning for similar halls. The study gave very specific and unique data on energy use in sport halls in cold climate. [ABSTRACT FROM AUTHOR]