I have an electric pool pump and am trying to figure out how many BTU's are given off during normal operation (let's say 1 hour). The specs are as follows:
I was told that there should be some formula to find this out; however I cannot seem to find it. Any help would be great.
Thanks, Doug
And learn to do high school math.
1 BTU = 1055.05585 joules 1 Watt = 1 joule / second
Conversion factor from watts to BTU/hour all well and good, but, still need to take into account efficiency of motor & pump. Presumably, some of the 750 watt power draw is actually used to pump water, as opposed to heating up case of motor....
W Letendre
0.75 kw/hr makes no sense, except as a rate of expansion of electric utility capacity. 1 kWh = 3412 BTU 1 hp = 746 W = 0.746 kW
At 1 hp for 1 hour, the BTU equivalent is
0.746 kW * 1 hr * 3412 BTU / kWh = 2545 BTU.At 230 V, 7.5 A, power is 1.725 kW. for 1 hour, this is 5886 BTU.
The differences are accounted for by whether the figures are ratings or figures about actual operation, and efficiency - shaft power delivered vs. total power consumed. I'm not sure what you mean by "given off". Is this a heat loss figure?
I certainly would have guessed that the OP was looking to calculate heating; BTUs are seldom used to measure anything else, and, as you say, the term "given off" is evocative...
Maybe the OP was looking to size air conditioner for pump shed?
WAG would be that motor on this rig runs ~ 85% efficient under load. Pump probably wastes another 10-20% of power in fluid flow viscous losses, but, that heat load will be carried out to the swimming pool in the water flow. Leaves (VERY roughly) either 380 or 880 BTU/hr, give or take, as heat dissipated by motor, depending on whether 1 hp or 1.725 KW is the motor's true power rating.
W Letendre
My swimming pool equipment "shed" is surrounded on three sides, the house and an approximately 5' block wall (stuccoed like the house).
Temperature rise from a 2HP pump is ~7°F :-(
...Jim Thompson
its 1.725kVA, 750W so a very low PF. in which case the efficiency is probably more like 70%. little motors have a favourable surface-area-to-volume ratio, so tend to be designed to be as cheap (IOW as lossy) as possible (NB modern motor standards are stomping out this sort of s***ty design practice), as they can get rid of the heat. so somewhere between 300 & 400 BTU (Bloody Terrible Unit)
Cheers Terry
The actual current drawn will depend on whether the pump rotor is designed to draw the motor's full power. It's likely actually a bit undersized, and the only way to know the actual consumption is to measure the current/voltage, i.e. a wattmeter. It will vary a lot depending on whether the filter needs backwashing too.
Clifford Heath.
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