Average Energy Efficiency Ratio Research Articles

Energy and economic efficiency of camelina and crambe biomass production on a large-scale farm in north-eastern Poland

The aim of this study was to determine the energy and economic efficiency of Camelina sativa and Crambe abyssinica production on a commercial plantation. The study was based on a three-year large-scale trial. The energy and economic inputs in the production of camelina and crambe were similar and were dominated by the consumption of fertilisers. The average yield of camelina and crambe seeds was very similar but the yield of camelina was more stable. The average energy gain from production of camelina was higher by 4.9% compared with the crambe. The average income from camelina seeds production (876.3 € ha−1) was higher by almost 12% than for crambe. The average energy efficiency ratio for production of camelina seeds (2.00) was higher by 5.7% compared with the crambe. The average energy efficiency ratio for the production of total biomass (seeds and straw) of camelina (4.74) was higher by 4.2% compared with the crambe. The revenue from camelina seeds was on average 312 € ha−1 and was 36% higher than that from crambe seeds, while the revenue from camelina total biomass production was on average 432.6 € ha−1 and was 26% higher than the value obtained from crambe production.

Effect of a Cumulative Cold and Heat Load Ratio on Hybrid Ground-Source Heat Pump System Performance Parameters

The imbalance in cold and heat load in large public buildings located in a cooling-dominated areas is apparent. To explore the effect of a cumulative cold and heat load ratio (CCHLR) on the performance parameters of the hybrid ground-source heat pump system (HGSHPS) of large public buildings, this study selects a Wuhan office building as the simulation object. When this model is considered as the prototype, five other building models whose CCHLR interval is relatively uniform can be developed. The full-year dynamic loads of the six models were calculated with Designer’s Simulation Toolkits. The 20-year simulation of the six HGSHPS models was conducted with TRNSYS. Then, the performance parameters of the HGSHPS model under different CCHLR values were studied and compared. These parameters included the average soil temperature, exiting fluid temperature (ExFT) of the ground heat exchanger (GHE), average energy efficiency ratio, and specific energy consumption (the electrical energy required to obtain per kilowatt cooling or heating capacity) of the heat pump system. Simulation results indicated that with the increase in CCHLR, the average soil temperature rapidly increases, the ExFT of the GHE increases to a value that is considerably higher than the suggested standard, and the specific energy consumption of the system increases.

Energy saving effect of building envelope in summer

To explore the energy saving effect of building envelope, the experiments were carried out through a comparison of basic cubicle in summer. Experiments show that if energy efficiency measures are applied only in the external walls and windows, the energy saving cubicles have an average energy efficiency ratio of 27.75% and 27.05% when the air change rates are 1.1 and 1.4 h−1 in summer, with both values being over the standard target value by 25%. And the indoor air temperature of the energy saving cubicle is below that of the basic cubicle. The daily mean temperature difference between the interior surface of insulation wall and no insulation reaches 1.47 °C, and the mean temperature difference is up to 8.52 °C between the interior surface and exterior surface of insulating glass and single glass. The two cubicles were simulated for energy consumption using VisualDOE4.0 software under real weather conditions in summer. The results show that the mean deviation is 10.02% between experimental and simulated energy efficiency ratio. The correctness and validity of simulation results of the VisualDOE4.0 software are proved.

New type of fresh air processor with liquid desiccant total heat recovery

A liquid desiccant total heat exchanger and small capacity refrigeration cycle combined fresh air processor is proposed here in this paper, in order to improve indoor air quality and decrease the energy consumption of the air-conditioning system. Operating principles of both the total heat recovery device and fresh air processor using liquid desiccant are presented in details. Experimental tests of the fresh air processor installed in a hospital show that energy efficiency ratio (EER) is around 6.3–7.3 in the summer experimental conditions and 4.7–5.0 in the winter experimental conditions. Hour-by-hour simulation, which is based on the climate data in Beijing, shows that the average EER is 5.3 and 4.3 in summer and winter period, respectively. Liquid desiccant has the potential to remove a number of pollutants, avoiding cross contamination. Furthermore, in summer fresh air is dehumidified by contacting liquid desiccant instead of 7 °C chilled water, which avoids wet surfaces in the air-conditioning system and much higher indoor air quality can be achieved.