Forum Home
PC World Chat
Thread ID: 67798	2006-04-06 06:46:00	Heatpump question	John W (523)	PC World Chat

Post ID	Timestamp	Content	User
444403	2006-04-06 06:46:00	Im considering putting in a heatpump in our house. The question being, would it be better place the compressor unit outside, or in a large basement garage, which has a steady temp range in Winter 8-12C instead of the outside which can be anywhere as low as from -8C. We wont need the cooling aspect of he heatpump. I figure I wont have any icing problems, the unit compressor will have a cleaner more stable temp range to work in, it will be secure and easier to work on, noise or drainage wont be a problem. Thanks John in Mosgiel.	John W (523)
444404	2006-04-06 06:55:00	There's nothing to stop you, but there are a couple of things to consider. You'll want to have reasonable insulation between the basement and the house to avoid cold feet. ;) The garage temperature will no longer be in the range 8-12 degrees. It will be cooler, possibly quite a lot ... the heat making the house warm is being extracted from the air in the garage. The ideal would be to have heat exchange pipes buried in the "earth".	Graham L (2)
444405	2006-04-06 07:28:00	Hi John. I have a firm arriving tomorrow, I hope, to install a heat pump. I understand that the outside unit will have a small but steady flow of moisture. So much so that the guys who have been here in the planning stage will be fitting a four metre long drain pipe to take the overflow on to the garden. How would that effect your basement?	Scouse (83)
444406	2006-04-06 07:45:00	Missed the Edit time: so an additional post: As to using basement - suggest you get installers to call and quote/advise. I rang the three biggest in Nelson and asked for a home visit. After six weeks one had only sent out a brochure full of jargon but two did send a rep. Different manufacturers options, similar sized hardware, within 6 dollars of each other on the quote. I went for broke and took the dearest.	Scouse (83)
444407	2006-04-07 21:58:00	As far as the compressor being inside or outside . . . it really depends on the climate there and you have to factor in that there is a heater in every compressor anyway to get the oil up to temp . That heater will be loaded pretty heavilly in the colder area, so I suggest to keep the wasted amps down to a minimum, find a relatively warmer location for the compressor . Compressors like to be running at about 200F degrees and that's why they will use the heater to get the temp up fast . That costs money . We run our heavy stuff for households on 240volts here in the States, as 120v would pull too many amps and raise the bills a lot . Heatpumps have not factored out as really an economical system . With the same voltages, and about the same climatic conditions (although youse guys are upside down and the seasons run counter to ours here), you will not see any great savings for running the heat pump system . . . in fact, just the opposite . The heatpump flash is over as we are getting used to higher and higher utility bills . . . they just didn't pencil-out well enough to install them in new buildings . Terminal re-heat systems wasted a lot of energy, but the dual system is still the best . Using an airconditioner (240v, 50 amp per leg) or an evaporative cooler with augmentation of a heater (natural gas WAS the cheapest), still is the most economical going . BTW: as I understand it, you still use the single leg 240 volt system with a terminal ground in most of NZ . . . . . . is this true? :waughh:	SurferJoe46 (51)
444408	2006-04-08 04:29:00	What are you talking about, Joe? Perhaps we have different (better?) thermodynamics here, as well as electrical supply . I believe that some people in NZ have had bad experiences with heatpump/air conditioners bought and imported on the basis of price, rather than specification . (People sometimes have problems when they buy computer items on price too) . Equipment made for other climates may not work properly when the outside temperature is below the level it's designed for . Perhaps this is a problem in the US, too . The compressor will warm up without external heating . It can't help it: PxVxT = constant, according to Mr Boyle . A 12KW air conditioner would be considered large here, Joe . Yes we use a multiple earthed neutral 230V single phase supply to most domestic installations . Bigger demand installations use 3 phase 230/415 .	Graham L (2)
444409	2006-04-08 05:06:00	What are you talking about, Joe? Perhaps we have different (better?) thermodynamics here, as well as electrical supply . I believe that some people in NZ have had bad experiences with heatpump/air conditioners bought and imported on the basis of price, rather than specification . (People sometimes have problems when they buy computer items on price too) . Equipment made for other climates may not work properly when the outside temperature is below the level it's designed for . Perhaps this is a problem in the US, too . The compressor will warm up without external heating . It can't help it: PxVxT = constant, according to Mr Boyle . A 12KW air conditioner would be considered large here, Joe . Yes we use a multiple earthed neutral 230V single phase supply to most domestic installations . Bigger demand installations use 3 phase 230/415 . No doubt that the compressor will heat up when it's running . . . but the cold start-up is the problem with congealed oil . That's the reason for the mullion heater . . . and a steady suck on the electrical supply to the tune of about 60 watts at 240v . Multiply that times 24/7/365 and it adds up to quite a bit . Anyway . . . the heatpump units which cool and heat by reverse flow, are not working out to be truly efficient here . Even with the 240v, 50amp legs, it cost a lot to run and the thermal losses are high . Our electrical bills are figured on 24 hour surge values . . . the big pull of start-up is the computational value for the next 24 hours, and can be quite high with cold oil in systems . . . . . a false sense of economy . It's always best to step out the hig amp pullers for the moment when a large device starts up . . . but most cannot afford or do not know of that process and pay dearly for that misconception . Our 240 is supplied from the pole drop in the form of two hot legs, a neutral and a ground . Typically, they use just the two legs in the drop with the cable that supports the legs as the neutral/ground . Each leg is 120v, usually about 50 to 80 amps for the average home . Combined, both legs deliver 100 to 160 amps at 240v . The home I live in is 240v/single phase/70 amps per leg . We do not have airconditioning or a heat pump . We use forced air heating from a central burner/blower arrangement, and an evaporative cooler that uses just plain ol' water and a circulating pump and a small squirrel cage blower at 120 v/10 amps . Quite thrifty and efficient too! In the United States and Canada, mains power (a NZ/Australian/UK term) is referred to by a variety of names, including household power (or household electricity), domestic power, wall power (because it comes from a power outlet in the wall), line power or simply "AC power . " A close synonym for "mains" in Canadian provinces that use hydroelectric power is "hydro" . ANSI standard C84 . 1 and Canadian standard CAN3-C235 specify that the nominal voltage at the output should be 120 V and allow a range of 114 to 126 V . Previously 110, 115 and 117 volts have been used at different times and places in North America . The question I had about single-leg 240 in NZ was in reference to the practice of sending just one leg of 240v to the domicile, and allowing the terminus to be the actual earth ground in the form of a copper rod driven into the ground for completing the circuit . This was the practice in early New York until it was discovered that enterprising persons could harvest all the electricity they wanted by inserting two copper rods into the ground and collecting the ground-effect current available there . ConEd (New York's primary electricity provider) put the end to that pretty soon when they found it out . :blush: As to climatic conditions: I honestly believe that NZ is pretty much the opposite of our weather here . . . season-wise, that is . We have extreme cold and hot areas like you . . . but the seasons are obverse . I therefor think that climatics are not an issue . . . just the timing of the seasons . . we are cold when you are hot . . . . . I still submit that heatpumps are energy non-efficient and wasters of resources . :nerd:	SurferJoe46 (51)
444410	2006-04-08 05:43:00	I understand the single 230v transmission line with earth return is only used in some back-block areas for cheapness. Back in about 1961 or 1962, Joseph Lucas Hydraulics and Combustion as it was called then, (or colloquially, Lucas Hot and Cold), carried out quite extensive research into heat pumps. At that time it was concluded they would only be satisfactorily efficient if the heat exchanger coils could be dunked in a convenient nearby stream :). Since then technology has advanced somewhat, but the principle of not having too great a temperature differential remains, so as you say they lose efficiency with climatic extremes. A bit like solar heating, when solar heating is high is when it is least needed (usually). What most existing domestic properties lack is adequately sized heat storage facilities.	Terry Porritt (14)
444411	2006-04-08 06:24:00	The "single line" distribution systems (SWER, or Single Wire Earth Return) is used only in a few remote rural areas, but there would be several hundred Km of it presently still going . There is a limit on the allowable earth current, so it's not able to service much in the way of load . The voltage limits here (Standard Low Voltage) are 230v +/- 6%, measured at the customer point of connection to the network . Typical domestic heat pumps are sized at 6 kW input power or less, which (under ideal conditions) will deliver an output of up to ~18 kW of heat . They are sold on the basis of "cheaper heating costs" but I have never seen anyone's power usage actually go down, just that their comfort level increases . The cooling effect in the summer is a bonus, but also increases the power consuption on an annual basis .	godfather (25)
444412	2006-04-08 06:50:00	""They are sold on the basis of "cheaper heating costs" but I have never seen anyone's power usage actually go down, just that their comfort level increases."" Mine was bought regardless of heating costs.... A couple of years ago I bought a good truckload of firewood, barrowed it from the front to the back of the house, spent days stacking it and so on. Spent several months humping the stuff from the stack to the pile near the woodburner on a daily basis. Swore that after a lifetime of such silly games that that was the last load ever. The trial run last evening convinced me that I've made the right decision. What astonishes me is that a lay-man can buy such a device knowing virtually nothing of the white-man's magic discussed above.	Scouse (83)
1 2 3 4