Environmental Impact Evaluation and Economy Analysis of Air-Conditioning Cold and Heat Source Based on TEWI Index

TEWI (total equivalent warming impact) index, a comparatively scientific method to evaluate the environmental impact of air-conditioning cold and heat source, is introduced. Taking some engineering in Hunan Province for example, the TEWI analysis was performed on the environmental impact assessment of four air-conditioning cold and heat source plans. Also the first investment and energy consumption were analyzed. The results indicate that: water loop heat pump unit, due to investment recovery period with only 2.9 years and carbon emission reduction up to 22.68%, has significant economy and environmental protection, which is followed by water source heat pump; the screw chilled water units plus gas boiler is poor. Gas direct-fired machine has certain economic advantage, but its environmental performance is general. Among four schemes, the proportion of indirect effects of CO2 emissions from fossil fuels used to generate energy to operate the equipment throughout its lifetime are all larger, respectively is 95.1%, 95.2%, 100% and 89.9%. It fully showed the importance of developing clean and renewable energy, reducing energy consumption and increasing performance coefficient of refrigeration and air conditioning device.