Concerns about the impact on the environment of the refrigerants used in HVAC&R equipment are driving the development of alternative refrigerants with lower global warming potentials (GWPs). This paper reports the performance of DR-55 (now designated as R452B), DR-5A (now designated as R454B), and R32 in comparison to R410A at the component level from tests run on a 4 RT (14 kW) commercial unit...

Evaporation of HFC134a inside smooth, horizontal tubes is studied. Te,;ts are made with pure refngerant and with oil-refrigerant mixtures. Heat flux has varied from 2 kW/n? to 10 kW/m . The inner diameter of the tubes are 12 mm. T1.1o evaporators are used, 4 and 10 m long. Oil content is varied from 0 to 2.5 mass percentage (synthetic oil, EXP-0275). Oil free HFC134a is found to have higher hea...

Models for unitary air conditioners and heat pumps typically have difficulties in providing accurate predictions for the following situations: 1) charge modeling over a large range of charge levels, 2) two-phase refrigerant entering fixed-orifice expansion devices, 3) two-phase refrigerant entering compressors, and 4) non-uniform refrigerant mass flow allocation among evaporator circuits at low...

as a generalization of the triple i method, the universal triple imethod is investigated from the viewpoints of both fuzzy reasoningand fuzzy controller. the universal triple i principle is putforward, which improves the previous triple i principle. then,unified form of universal triple i method is established based onthe (0,1)-implication or r-implication. moreover, the reversibilityproperty o...

The present work investigates the thermodynamic optimality of a double-effect vapor absorption refrigeration system (VARS) driven by blowdown heat 210 MW thermal power plant at Badarpur using response surface methodology (RSM). RSM helps to develop relation amongst decision variables and second law efficiency vi se cond-order nonlinear polynomial regression equation. In addition, analysis varia...