This study reports the numerical analyses of a CO2 transcritical cycle on solar assisted heat pump water heating system in which evacuated tube U-pipe solar collector is utilized as an evaporator. This simulation model can predict operating characteristics for moderate meteorological conditions of North Dakota. The main purpose of this work is to simulate the overall performance of the heat pum...

The variation of refrigerant mass in the cylinder of refrigerator compressor has a great influence on the compressor’s thermodynamic process. In this paper, the m-θ diagram, which represents the variation of refrigerant mass in compressor cylinder (m) and the crank angle (θ), is proposed to investigate the thermodynamic process of the refrigerator compressor. Comparing with the traditional pres...

The performance of oil-flooded screw comp ressors depends on a large number of design paramet ers such as rotor profile, number of rotor lobes, rotor L/D ratio, wrap angle, geometrical clearance s, quantity and location of oil injection, discharge port size and tip speed. Knowledge of the effect of these parameters can help a designer to select the best performing machine for a given applicatio...

The flow of gas in the suction chamber of an air brake compressor was analyzed, and losses due to pressure drop and heat transfer were identified by CFD simulations. Based on the results of the calculations the geometry of the suction chamber was modified to investigate possible improvements. Due to simple design modifications the flow direction of the gas was changed, which resulted in a reduc...

This paper presents a challenging industrial benchmark for implementation of control strategies under realistic working conditions. The developed control strategies should perform in a plug & play manner, i.e. adapt to varying working conditions, optimize their performance, and provide fault tolerance. A fault tolerant strategy is needed to deal with a faulty sensor measurement of the evaporati...

This paper identifies weak points in the control of commercial DC variable-speed compressors, fed by photovoltaic panels, and describes the development of an energy-efficient control method. The method can be used in any application requiring such compressors to be driven by PV's, either for heating or cooling purposes. The advantage of using the presented method is the improved utilization of ...

Reciprocating compressors are most common type of compressor and most flexible machine to handle wide capacity and condition swings. They offer a most efficient method of gas compressing. They are vital machines in various units of industrial plants. In this paper advanced technologies and latest configurations and methods regarding condition monitoring, performance, flow management, capacity c...

In order to study the matching characteristics of positive displacement air compressor and PEMFC (proton exchange membrane fuel cells), supply subsystem, basic operating performance parameters scroll single-screw compressors were analyzed with focus on oil-free double-wrap compressor. According thermodynamic model three-dimensional unsteady-state numerical simulation, variation temperature, pre...

The compressor motor of an air conditioner is subjected to the a fluctuating load torque during suction and discharge refrigerant, resulting in speed ripple machine angular cycle. This paper proposes new predictive feedforward control system that predicts suppresses cuased by periodic disturbance using error data PI controller. suppression performance proposed method experimentally confirmed ap...

Abstract: This paper is focused on the performance of centrifugal compressors for vehicle turbochargers operating at high altitude. The reasons for turbocharged diesel engine power loss increases and bad economy performance caused by exhaust gas energy utilization are investigated. The atmosphere’s impact on the turbocharger centrifugal compressor’s energy distribution characteristics under the...