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Record 1 of 3329
Solar-Powered Refrigeration System
Availability: Go to Request Form
Author and Affiliation:
Ewert, Michael K. [Inventor](NASA Johnson Space Center, Houston, TX United States)
Bergeron, David J., III [Inventor](NASA Johnson Space Center, Houston, TX United States)
Abstract: A solar powered vapor compression refrigeration system is made practicable with thermal storage and novel control techniques. In one embodiment, the refrigeration system includes a photovoltaic panel, a variable speed compressor, an insulated enclosure, and a thermal reservoir. The photovoltaic (PV) panel converts sunlight into DC (direct current) electrical power. The DC electrical power drives a compressor that circulates refrigerant through a vapor compression refrigeration loop to extract heat from the insulated enclosure. The thermal reservoir is situated inside the insulated enclosure and includes a phase change material. As heat is extracted from the insulated enclosure, the phase change material is frozen, and thereafter is able to act as a heat sink to maintain the temperature of the insulated enclosure in the absence of sunlight. The conversion of solar power into stored thermal energy is optimized by a compressor control method that effectively maximizes the compressor's usage of available energy. A capacitor is provided to smooth the power voltage and to provide additional current during compressor start-up. A controller monitors the rate of change of the smoothed power voltage to determine if the compressor is operating below or above the available power maximum, and adjusts the compressor speed accordingly. In this manner, the compressor operation is adjusted to convert substantially all available solar power into stored thermal energy.
Publication Date: Oct 22, 2002
Document ID:
20020089611
(Acquired Dec 06, 2002)
Subject Category: ENGINEERING (GENERAL)
Report/Patent Number: US-Patent-6,469,487, US-Patent-Appl-SN-838679, US-Patent-Appl-SN-337208, NASA-Case-MSC-22970-2
Document Type: Patent
Financial Sponsor: NASA Johnson Space Center; Houston, TX United States
Organization Source: NASA Johnson Space Center; Houston, TX United States
Description: 10p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: No Copyright
NASA Terms: CONTROL SYSTEMS DESIGN; REFRIGERATING MACHINERY; ENCLOSURE; HEAT STORAGE; SOLAR ENERGY CONVERSION; PATENTS; PRODUCT DEVELOPMENT; RESEARCH AND DEVELOPMENT; COMPRESSORS; REFRIGERANTS; CONTROLLERS
Miscellaneous Notes: Division of US-Patent-Appl-SN-337208, filed 3 Jun. 1999
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