Controllability of cross-flow two-phase heat exchangers

Dı́az, Gerardo

doi:10.1016/j.ijheatmasstransfer.2007.03.024

Cited by 10 publications

(1 citation statement)

References 20 publications

(30 reference statements)

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“…Since the electromechanical process of reaching the compressor operational speed is faster than the associated thermal process, its transient characteristics can be neglected [2] and modelled by just algebraic equations [21]. Therefore, the compressor is modelled with the use of an iterative procedure described by the refrigerant mass flow rate of the compressor, the polytropic work input to the compressor and the refrigerant enthalpy at the compressor exit.…”

Section: Compressormentioning

confidence: 99%

Modeling and experimental validation of a solar-assisted direct expansion air conditioning system

Vakiloroaya

Skibniewski

2013

Energy and Buildings

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Continuous increase in global electricity consumption, environmental hazards of pollution and depletion of fossil fuel resources have brought about a paradigm shift in the development of ecofriendly and energy-efficient technologies. This paper reports on an experimental study to investigate the inherent operational characteristics of a new direct-expansion air conditioning system combined with a vacuum solar collector. Mathematical models of the system components are firstly derived and then validated against experimental results. To investigate the potential of energy savings, the hybrid solar-assisted air-conditioner is installed and extensively equipped with a number of sensors and instrumentation devices, for experimentation and data collection. The influence on the system energy usage of the average water temperature, storage tank size and room set-point temperature are then analyzed. Once the air-conditioned room has achieved its desired temperature, the compressor turns off while the cooling process still continues until the refrigerant pressure no longer maintains the desired temperature. The advantages of the proposed hybrid system rest with the fact that the compressor can remain off in a longer period by heat impartation into the refrigerant via the water storage tank. Results show an average monthly energy saving of about between 25% and 42%. AbstractContinuous increase in global electricity consumption, environmental hazards of pollution and depletion of fossil fuel resources have brought about a paradigm shift in the development of ecofriendly and energy-efficient technologies. This paper reports on an experimental study to investigate the inherent operational characteristics of a new direct-expansion air conditioning system combined with a vacuum solar collector. Mathematical models of the system components are firstly derived and then validated against experimental results. To investigate the potential of energy savings, the hybrid solar-assisted air-conditioner is installed and extensively equipped with a number of sensors and instrumentation devices, for experimentation and data collection. The influence on the system energy usage of the average water temperature, storage tank size and room set-point temperature are then analyzed. Once the air-conditioned room has achieved its desired temperature, the compressor turns off while the cooling process still continues until the refrigerant pressure no longer maintains the desired temperature. The advantages of the proposed hybrid system rest with the fact that the compressor can remain off in a longer period by heat impartation into the refrigerant via the water storage tank. Results show an average monthly energy saving of about between 25% and 42%.Keywords: energy saving, solar-assisted air conditioner, modeling, experimental validation, performance prediction. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47...

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Section: Compressormentioning

confidence: 99%