# Comment: unless you have a free source

(See in situ)

### unless you have a free source

unless you have a free source for ice daily and the icemaker is not in your house. Then this cost more then an ac. This saves you nothing unless you have a free source of ice and it is not in your house producing heat since making ice still produces heat in the house.

The only way this is cheaper is if you have no source for electricity and you use solar to run the small fan but you still need free ice or a way to make the ice which produces heat and makes this unit more costly then an ac. Unless you have a 100% free source for ice.

This unit is waste of time and money since ice cost money to buy or produces heat to make it with electricity through a fridge.

If you like wasting money and time this is a great idea.

bottom line if you have to buy or make the ice then it will cost more to run this then an ac with electricity. simple math

Ok, lets assume that you could cool your room either with a single bag of ice in this device, OR a single window air conditioner. Which would be cheaper, assuming you needed one bag of ice per day?

A small air conditioner is defined as using less than 7.5 amps. Lets assume 7.5. Then at 120V, we use 7.5*120=900W *24hrs= 21.6kWh. In ontario (averaged over 24hrs), energy is 9.05c/kWh, so we use 21.6kWh*0.0905\$=\$1.96 of electricity per day

So, in the absolute worst case (max amperage, 24hr at full power) the AC unit less (or equal if you have cheap ice) electricity as a bag of ice costs.

So, in the best case of the proposed ice cooling (1 bag/day, free electricity, free transportation of ice), it isn't worth it.

Edit: or we can look at it this way: A really efficient AC unit has an EER of 10. This means that (if it is the 7.5A unit above), it produces 9000 Btu of cooling, or 9495 kJ. The enthalpy of fusion (energy to melt) of ice is 334 kJ/kg. So every hour this AC unit produces cooling equivalent to melting about 28kg of ice. A bad EER might be about 5, so 14kg of ice. I think a bag of ice is around 2kg? And this is per hour.

note then folks will say but the freezer is already running anyway, well

Thats not how freezers work. Your freezer does a little work all the time maintaining temperature, as the insulation is only so good. It does a lot of work freezing new stuff you add. So you incur costs equal to the chilling ability of the freezer to make that ice (it takes that same 334kJ/kg to freeze ice as it does to melt it). Substitute some numbers for your freezer to my above equation to see how much it costs to freeze ice in your freezer. Chances are it is similar to the AC (both are moving heat from inside to outside).

Laws of thermodynamics and all that says it takes more energy (dissipated as heat out the back of the freezer) to freeze water than is available to use as chilling when you melt it. It comes from the inability to be perfectly efficient.

An AC unit has one advantage over the ice-in-freezer. The water that is condensed out of your air is sprayed by the fan over the external cooling coil, and is used to increase efficiency by evaporating water (huge latent heat sink), rather than just passing air over the coils/radiator (which both AC, freezers, and fridges do)

TL;DR: no free lunch, you pay electricity to create ice, and it is less efficient than an AC unit.

Ron Paul 2016