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Modeling the Effects of Refrigerant Charging on Air Conditioner Performance Characteristics For Three Expansion Devices
(1990-08)
An experimental and analytical study concerned with the off-design refrigerant charging of air conditioners is presented. A series of experiments were conducted to characterize the effects of refrigerant charge and type ...
Numerical Modeling of the Transient Thermal Interference of Vertical U-Tube Haet Exchangers
(1994-12)
Non-linear finite element models were developed to simulate transient heat and mass transfer in the soil surrounding the ground heat exchangers of ground-coupled heat pumps (GCHPs) operating in the cooling mode. Parametric ...
A Study of Transient Behavior During Start-Up of Residential Heat Pumps
(1989-12)
An experimental and analytical study concerned with the transient performance of heat pumps is presented. A series of tests were performed to study and characterize the transient sensible and dehumidification performance ...
Analysis of Mass Flow and Enhanced Mass Flow Methods of Flashing Refrigerant-22 from a Small Vessel
(1994-12)
The mass flow characteristics of flashing Refrigerant-22 from a small vessel were investigated. A flash boiling apparatus was designed and built. It was modeled after the flashing process encountered by the accumulator of ...
Two-Phase Flow of HCFC-22 and HFC-134a through Short Tube Orifices
(2008-01-23)
HCFC-22 and HFC-134a were used with short tube orifices having length to diameter ratios ranging from 5 to 20 in a 9.53 mm (3/8 in.) refrigerant line to investigate both two-phase and subcooled liquid flow entering the ...
A Methodology to Measure Retrofit Energy Savings in Commercial Buildings
(2008-01-16)
Measured energy savings promote and sustain energy conservation retrofits by verifying the success of retrofits, determining pay-back schedules, guiding the selection of future retrofits and identifying opportunities for ...
The Persistence of Savings Obtained from Commissioning of Existing Buildings
(2008-06-10)
The objective of this study is to investigate the reasons why the performance of
mechanical systems degrades over time after commissioning and to recommend intervals
at which testing should be performed to maintain the ...
An Experimental Investigaton of the Effect of Oil on Convective Heat Trasfer and Pressure Drop of a HFC-32/HRC-125 Mixture
(1994-12)
The heat transfer coefficients and pressure drops of HCFC-22 and a 50% mass mixture of HFC-32/HFC-125 were experimentally measured under flow boiling conditions in a smooth tube. The refrigerants were flowed through an 8 ...
Development and Application of a Procedure to Estimate Overall Building and Ventilation Parameters from Monitored Commercial Building Energy Use
(1997-05)
This thesis proposes and validates a simplified model appropriate for parameter identification and evaluates several different inverse parameter identification schemes suitable for use when heating and cooling data from a ...
Study of Air Infiltration Energy Consumption
(1992-08)
The influence of heat recovery on the energy impact of air infiltration, and the systematic error due to the steady-state method were studied both experimentally and theoretically. Two methodologies suitable for measurement ...