Before selecting a A/C unit, a calculation of how much heat gain or lost there is between a inside surface of a structure and the outside structure.
One ton of A/C is equal to 12,000 bturs. 3420 bturs equal 1000 watts. The formula is: bturs = SF x u factor x TD SF is the square foot area of the exterior surfaces U is equal to 1/R TD is the Temperature Difference between the temperature of the outside surface to the inside surface. Calculation for a passenger compartment of a vehicle not insulated: Single pane class is 1 R-Factor Single panel of sheet metal is 1 R-Factor Therefore the u-factor is 1/R = 1u. For heating loss, we use 100 F. degree temperature difference (TD) to maintain a interior temperature of 70 F. at 30 below 0. or TD = 100 For A/C heat gain, we use a 70 F. degree temperature difference (TD) to maintain a interior temperature of 70 F. at 140 F ambient or TD = 70 The calculation which I use for my EV: My SF = 175 SF of the interior passenger The u-factor would be 1/1 or 1U if not insulated The TD = 70 F. Therefore: Btur's = 175 SF x 1 U-factor x 70 F TD = 12250 bturs. One ton of A/C = 12000 btur's Minimum size of A/C unit will be 12250/12000 = 1.02 ton Adding insulation which I install two layers of 1 inch soft foam in the door panels and firewalls. Insulated the floor with 1 inch of firm DOW blue board foam with a layer of 1 inch soft foam and carpet. This reduce the btur's to about half. Heating only takes 640 watts at 120 vac 60 hz (continuous ON) at 0 F. If I want the heater to cycle, than I switch in another 740 watt heater. The power comes from my rotating inverter/alternator that is rated at 7kw. Roland ----- Original Message ----- From: Jan Steinman via EV<mailto:ev@lists.evdl.org> To: ev@lists.evdl.org<mailto:ev@lists.evdl.org> ; ev-requ...@lists.evdl.org<mailto:ev-requ...@lists.evdl.org> Sent: Saturday, August 02, 2014 11:22 PM Subject: Re: [EVDL] Hybrid Mustang: AC or DC? > From: Ben Goren via EV <ev@lists.evdl.org<mailto:ev@lists.evdl.org>> > > ... are there heat pump systems rather than compressor units that might be more energy efficient? The compressor-based system in almost all consumer things that reduce temperature *is* a heat pump. The only one that I know of that is different is the "Einstein evaporator" used in many multi-powered camping refrigerators. :::: Rapid growth in the human energy base has broken down old biological and cultural diversity, and simultaneously led to proliferation of human numbers and individual diversity. The climaxing and decline of energy will inevitably result in a reduction of human numbers, and possibly individual diversity, while stimulating the re-emergence of localised biological and cultural diversity. -- David Holmgren :::: Jan Steinman, EcoReality Co-op :::: _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub<http://www.evdl.org/help/index.html#usub> http://lists.evdl.org/listinfo.cgi/ev-evdl.org<http://lists.evdl.org/listinfo.cgi/ev-evdl.org> For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA<http://groups.yahoo.com/group/NEDRA>) -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140803/0d01e1bc/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
