High efficiency novel window air conditioner

Abstract

h i g h l i g h t sUse of novel refrigerant mixture of R32/R125 (85/15% molar conc.) to reduce global warming and improve energy efficiency. Use of novel features such as electronically commuted motor (ECM) fan motor, slinger and sub-merged sub-cooler. Energy savings of up to 0.1 Quads per year in USA and much more in Asia/Middle East where WACs are used in large numbers. Payback period of only 1.4 years of the novel efficient WAC. a b s t r a c tThis paper presents the results of an experimental and analytical evaluation of measures to raise the efficiency of window air conditioners (WAC). In order to achieve a higher energy efficiency ratio (EER), the original capacity of a baseline R410A unit was reduced by replacing the original compressor with a lower capacity but higher EER compressor, while all heat exchangers and the chassis from the original unit were retained. Subsequent major modifications included -replacing the alternating current fan motor with a brushless high efficiency electronically commutated motor (ECM) motor, replacing the capillary tube with a needle valve to better control the refrigerant flow and refrigerant set points, and replacing R410A with a 'drop-in' lower global warming potential (GWP) binary mixture of R32/R125 (85/15% molar concentration). All these modifications resulted in significant enhancement in the EER of the baseline WAC. Further, an economic analysis of the new WAC revealed an encouraging payback period.

Effect of the Slinger Ring on the Forced Convection Heat Transfer in a Window Air Conditioner

“…For WACs, the slinger effect [1] was investigated by the experimental research of Bansal [2], Shen and Bansal [3], and Shen and Fricke [4]. These experiments [2][3][4] adopted a simple approach to treat the slinger effect as an air side heat-transfer enhancement factor based on the experimental data, instead of modeling the heat and mass transfer process.…”

“…Bansal [2] drilled a hole at the bottom of a WAC in the condenser fan that allowed the condensed water to be collected in a bucket, eliminating any entrained water from blowing over the condenser, in order to assess the slinger effect on the performance of the WAC. The system's estimated energy requirement was found to decrease by approximately 8%, compared to the baseline data, without the submerged sub-cooler and the slinger.…”

“…The previous experiments of Bansal [2], Shen and Bansal [3], and Shen and Fricke [4] also focused on refrigerants and other techniques for WACs with a slinger ring. Thus, there were no results for the multiphase flow and thermal fields in a WAC with a slinger ring in the experiments of Bansal [2], Shen and Bansal [3] and Shen and Fricke [4]. Furthermore, based on authors' literature review for WACs, except for these studies, it is difficult to find research that considers slinger rings installed on WACs.…”

A new capacity controller for a direct expansion air conditioning system for operational safety and efficiency

“…Therefore, DX A/C systems are extensively used in different types of buildings, especially in small-to medium-scale ones. 3,4 With the application of variable speed (VS) technology to DX A/C systems, compressor and supply air fan speeds in a DX A/C system can be simultaneously varied by using variable speed drives (VSD), paving the way to simultaneously control indoor air temperature and humidity. In a VS DX A/C system, as the variation in its compressor and supply fan speeds will lead to the corresponding changes in the output sensible and latent cooling capacities, the different sensible and latent cooling loads in the space served by the DX A/C system could be satisfied through varying both compressor and supply fan speeds and thus the simultaneous control over indoor air temperature and humidity achieved.…”