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...

In the energy-saving research developments in recent years, many types of research project on high performance heat pump systems are under development It is required to estimate the thermodynamic performance of these thermal cycles on a common scale by applying an adequate method. a basic cycle of two stage condensation heat pump system is considered. Steady state conditions are analyzed for th...

The heating capacity and coefficient of performance (COP) of conventional air-source heat pumps decreases towards lower ambient temperatures. Additionally, the heat pump stops running at very low ambient temperatures due to the high discharge temperature at the outlet of the compressor. Oil injected into the compression chamber absorbs the heat generated during the compression process and thus,...

As global warming has raised more critical concerns in recent years, refrigerants with high global warming potentials (GWP) are facing the challenges of being phased out. R410A, with a GWP of 2,088, has been widely used in residential air-conditioning and heat pump systems. A potential substitute for R410A is R32, which has a GWP of 675. This paper investigates the performance difference of R41...

four kinds of refrigerant mixtures R22/Rl34a, R22/Rl52a, R22/Rl42b and R22/Rl23, which contain some new halocarbons which are considered to be the alternatives for CFCs, were evaluated in order to realize higher condensing temperature than that using R22 at high temperature operation, and larger heating capacity than that using R22/Rll4 at normal temperature operation. These mixtures were appli...

As global warming has raised more critical concerns in recent years, refrigerants with high global warming potentials (GWP) are facing the challenges of being phased out. R410A, with a GWP of 2,088, has been widely used in residential air-conditioning and heat pump systems. A potential substitute for R410A is R32, which has a GWP of 675. This paper investigates the performance difference of R41...

The main purpose of this paper is to analyze the sensitivity of system parameters to the performance of the Organic Rankine Cycle (ORC) system quantitatively. A thermodynamic model of the ORC system for binary-cycle geothermal power plants has been developed and verified. The system parameters, such as working fluid, superheat temperature, pinch temperature difference in evaporator and condense...

An updraft tower cooling system is assessed for elimination of water use associated with power plant heat rejection. Heat rejected from the power plant condenser is used to warm the air at the base of an updraft tower; buoyancy-driven air flows through a recuperative turbine inside the tower. The secondary loop, which couples the power plant condenser to a heat exchanger at the tower base, can ...