Article 28734 of alt.energy.homepower: Path: news.vill.edu!not-for-mail From: nick@pluto.ee.vill.edu (Nick Pine) Newsgroups: sci.engr.heat-vent-ac,alt.energy.homepower,alt.energy.renewable Subject: Re: More about.. Re: Can we use compressed air for refrigeration ?? Date: 19 Apr 2000 06:49:20 -0400 Organization: Villanova University Lines: 26 Message-ID: <8dk2vg$l5a@pluto.ee.vill.edu> References: <8d6bbq$gan$1@freenet9.carleton.ca> <38F704FE.8B0D41E6@matonak.org> <38fae48c.1074065@nsw.nnrp.telstra.net> NNTP-Posting-Host: pluto.ee.vill.edu Xref: news.vill.edu sci.engr.heat-vent-ac:23738 alt.energy.homepower:28734 alt.energy.renewable:33520 H. Myler wrote: >We shoot ourselves in the foot when it comes to refridgerators and the >way they are designed. Imagine a very heavily insulated box with only a >narrow window at about chest height. On one side is a large wheel (a >pair of buttons on the deluxe model) And maybe a coin slot :-) >...when you turn it trays appear in the window. The trays hold the food. >After you locate what you need you open the window and take it out. Very, >very little loss and no more standing at the fridge with the door open >trying to decide! I would bet that a unit such as that could gain 25% >efficiency over the standard door models. How much would you bet? A 3x4x5' box with 4" Styrofoam walls and 94ft^2/R20 = 4.7 Btu/h-F of thermal conductance needs 24h(70F-35F)4.7Btu/h-F = 3,948 Btu/day (1.2 kWh of coolth or ~400 Wh of electrical energy) to stay 35 F in a 70 F room. Opening the door 20 times per day with no condensation adds about 20(70F-35F)3x4x5/55 = 764 Btu to that for a total of 4,712 Btu. A 1'x1' R4 window adds 0.25 Btu/h-F to the conductance to make 4,158 Btu/day with the door closed, which looks like a maximum 12% savings. Nick