Refrigeration efficiency. Ge profile series refrigerator
- the process of cooling or freezing (e.g., food) for preservative purposes
- (refrigerant) any substance used to provide cooling (as in a refrigerator)
- deliberately lowering the body's temperature for therapeutic purposes; "refrigeration by immersing the patient's body in a cold bath"
- the ratio of the output to the input of any system
- The state or quality of being efficient
- An action designed to achieve this
- The ratio of the useful work performed by a machine or in a process to the total energy expended or heat taken in
- skillfulness in avoiding wasted time and effort; "she did the work with great efficiency"
- (efficient) effective: able to accomplish a purpose; functioning effectively; "people who will do nothing unless they get something out of it for themselves are often highly effective persons"-G.B.Shaw; "effective personnel"; "an efficient secretary"; "the efficient cause of the revolution"
refrigeration efficiency - Thermodynamic analysis
Thermodynamic analysis and determination of spontaneous emission quantum efficiency for luminescence refrigeration in semiconductors.
Luminescence refrigeration in semiconductors has recently attracted much interest and has developed into an active area of research. This dissertation focuses on understanding the fundamental mechanisms of luminescence refrigeration. To fulfill this task, the thermodynamic principles of luminescence refrigeration in semiconductors are investigated based on the balance equations for energy, entropy, and particle number. By taking background radiation into account, the output and input fluxes are examined using a thin-slab model in the steady state, through which the cooling efficiency and cooling power are obtained. The concept of radiation flux temperature is clarified and the origination of irreversible entropy generation during luminescence is investigated. The Eddington factor is also discussed. High material quality is critical to the achievement of net cooling in luminescence refrigerators. To this end photoluminescence spectroscopy is utilized to characterize molecular beam epitaxy (MBE) grown samples; this information is then fed back to the growth of GaAs based luminescent devices to ensure the highest quality materials. The impact of Sb mediated growth on the performance of GaAs/AlGaAs materials is also studied. Moreover, the MBE system is precisely calibrated to ensure the accurate growth of device structures. The MBE calibration procedures using reflectance measurements and the growth rate calibration curves versus cell temperature for GaAs, AlAs, and InAs, the As/III overpressure versus As cell valve setting, and the dopant concentrations versus dopant cell temperatures are also presented. Spontaneous emission quantum efficiency is one of the most important parameters in luminescence refrigeration. The injection and temperature dependence of the spontaneous emission quantum efficiency in GaAs/AlGaAs heterostructures and InGaAs/GaAs quantum wells is studied using photoluminescence measurements performed at temperatures from 50 to 320 K using a HeNe pump laser with power ranging from 0.6 to 35 mW. The quantum efficiency is inferred from the power law relations predicted by the rate equations that link pump power and integrated photoluminescence signal. For the GaAs/AlGaAs heterostructures, the use of Sb mediated growth improved the extrapolated peak spontaneous emission quantum efficiency from 0.970 to 0.977 at 300 K, with the best overall performance from 0.996 to 0.998 at 180 K. For the InGaAs/GaAs quantum well structure, the extrapolated peak spontaneous emission quantum efficiency is 0.941 at 300 K, with a best overall performance of 0.992 at 100 K.
June 24, 2009: On behalf of Efficiency Maine, John Brautigam presented Fred Forsley with a recognition award for all the green technologies at the Shipyard Brew Pub and Regatta Banquet & Conference Center in Eliot, Maine. A roof top solar system is the backbone of an energy efficient system that includes features such as: heated sidewalks; interior, exterior, and parking lot lighting; low energy, high efficiency kitchen motors; recaptured heat from refrigeration motors; preheated water; and cooking systems that utilize steam generated by natural gas. This award recognizes the commitment to energy efficient practices Shipyard Brewing Company has demonstrated. Maine's director of tourism, Pat Eltman, was also on hand to talk about the importance of green businesses to Maine's tourism industry. The Shipyard Brew Pub and Regatta Banquet & Conference Center are both located in Eliot Commons on Route 236 in Eliot, Maine. Just 1 hour north of Boston or 1 hour south of Portland. regattaroom.com
America's Second Harvest of the Big Bend
The Tallahassee, Fla.-based organization will use its $72,973 grant from the Walmart Foundation to add insulation around its refrigeration equipment, upgrade the controls on its heating and air conditioning systems and retrofit old lighting with new, more efficient technology. These improvements are expected to save more than $22,000 in energy costs each year, which America’s Second Harvest of the Big Bend says could help provide 80,000 more meals to its communities.
This comprehensive, hands-on manual covers all of the procedures necessary to fine-tune HVAC/R systems for optimum operating efficiency. Easy-to-follow guidelines and worksheets guide readers through each step of the process, giving them the tools they need to assure that equipment can operate at peak efficiency as designed by the manufacturer. The full spectrum of systems and equipment are covered, including electric heating, gas heating, oil burners, air conditioning systems, heat pumps, and refrigeration equipment. A wealth of helpful diagrams, illustrations, estimating tools, and worksheets are also provided. Multiple tear-out copies of each worksheet are provided for use on the job.