Using tap water to cool down the fridge

goblinsly · 07-03-13, 06:23 AM

Hey everyone,

In my apartment, my fridge is only a few meters away from my bed and no wall in between. Fridge noice bothered me at night soo i decided to enclose it in a closet and add fans to cool off the compressor and coils. I already finished the idea but that is not why i made this post.

I have my fridge near the sink. The water coming out of the pipe is cold, probably 15C. This is the only water pipe i have apart from the shower. This means i use it quite a lot. I measured the height and it would be quite simple to connect the outlet of the sink to go through a copper pipe that would touch the fridge coils and then out. The idea is that when the fridge works, the copper pipes would heat a lot ( tested it ) and when i would drop the water with only 15C, the difference would be enough to take a lot of heat of them. It would also be possible to leave a small amount of water in the pipes at all times, giving the fridge time to heat them ... and then when i use water to wash things, new cold water would simply push away the hot water in them.

I use water sink maybe every hour or every 2 hours ... and my fridge works for 30-40 minutes and then rests for 60-80 minutes. That means that basicly i would cool the fridge on every cycle this way.

This would work good in the summer to remove some of the heat but if my understanding of the way fridge works, it would also make the cycle shorter - less energy usage.

I got this idea because i wanted to create a simple watercooling for the fridge .. but then i thought ... why create a pump using the electricity and fans ... if i can just use gravity ... and i use the water anyway .. i eat 4+ times a day and i wash the plate afterwards ... i wash my hands when i use the bathroom .. etc. There is a good height difference between the sink and the hole where water leaves the apartment ... with a small copper tube i could twist it a few times ... creating a big area of cooling ... When my fridge works, it uses about 250W says the killawatt .. in the summer that is quite a lot of heat, if you manage to remove it from the apartment ..

Soo, what do you think ?

jeff5may · 07-03-13, 09:11 PM

Many people have done this. google the term:

Greywater heat recovery

Most greywater systems are used to preheat the hot water supply line before it gets to the water heater. The idea is to reclaim this wasted heat before it leaves down the drain. Your idea of dumping waste heat into the drain line would also work well. Good luck!

BEWARE: This thought process leads to more energy-saving ideas!

nexsuperne · 07-04-13, 03:44 PM

Using the heat from the coils is just how an air to water heat pump works. I have a commercial client that runs huge freezers (the size of a house), initially, all the waste heat was lost to the fresh air outside, until I persuaded him that an ashp to preheat his sterilizer water tank would save a large amount of money. We now have that powered with solar pv, and then an additional array of 600 evacuated tubes to get the sterilizer water tank to 95C. On a sunny day, he can run the plant for nothing!

goblinsly · 07-04-13, 07:33 PM

Great to hear that this ideas actualy work !

For now i am only interested in cooling down the fridge and taking that heat out by using tap water ... right now i dont have the time or finances to use that hot water for anything ... i am using a gas powered furnace that heats water on demand, it doesnt store it. I do know that fridge will use less electricity since it will run cooler and soo the cycles will be shorter but more importaint, during the summer my apartment will be a tiny bit cooler ( not much though ). I do have some ideas for the future ... when i will have the time.

Let me just say that i am very glad i found this forum. I have lots of "macgyver" ideas and its good that there is a place where i can verify or debate about them.

goblinsly · 07-31-13, 05:36 AM

If i could just use this topic to ask another thing ....

My fridge is working for 30 mins and then resting for 60 mins. I noticed that as soon as the fridge turns off, the fans cool off the coils in a couple of minutes and then keep blowing but all the work goes to waste...soo i am thinking of adding more material and connect it to the coils .. this means there will be more material to be heated in this 30 minutes and therefor the coils will have the lower temperature ... and as the fridge turns off, in those 60 mins it will get cooled down.

I am pretty sure this should work because in those 60 mins, the coils always get cooled down to near air temperature. Soo basicly the only thing that matters is making sure that those 30 mins when compressor runs, there is a lot of material absorbing heat and in turn making the gas in pipes cooler ...

razor02097 · 07-31-13, 08:17 AM

I assume you have a fridge with the coils underneath? The fan not only helps to move the rest of the heat out from the coils but also keep air flowing around the compressor.

Just keep in mind the appliance was manufactured with a certain tolerance in mind for airflow to cool off the coils, as well as the surface area for the coil. By adding material you raise the mass and the ability to absorb heat but also reduce surface area and potentially airflow. This could potentially reduce efficiency.

07-03-13, 06:23 AM	#1
goblinsly Lurking Renovator Join Date: Jul 2013 Location: Slovenia Posts: 17 Thanks: 0 Thanked 1 Time in 1 Post	Using tap water to cool down the fridge Hey everyone, In my apartment, my fridge is only a few meters away from my bed and no wall in between. Fridge noice bothered me at night soo i decided to enclose it in a closet and add fans to cool off the compressor and coils. I already finished the idea but that is not why i made this post. I have my fridge near the sink. The water coming out of the pipe is cold, probably 15C. This is the only water pipe i have apart from the shower. This means i use it quite a lot. I measured the height and it would be quite simple to connect the outlet of the sink to go through a copper pipe that would touch the fridge coils and then out. The idea is that when the fridge works, the copper pipes would heat a lot ( tested it ) and when i would drop the water with only 15C, the difference would be enough to take a lot of heat of them. It would also be possible to leave a small amount of water in the pipes at all times, giving the fridge time to heat them ... and then when i use water to wash things, new cold water would simply push away the hot water in them. I use water sink maybe every hour or every 2 hours ... and my fridge works for 30-40 minutes and then rests for 60-80 minutes. That means that basicly i would cool the fridge on every cycle this way. This would work good in the summer to remove some of the heat but if my understanding of the way fridge works, it would also make the cycle shorter - less energy usage. I got this idea because i wanted to create a simple watercooling for the fridge .. but then i thought ... why create a pump using the electricity and fans ... if i can just use gravity ... and i use the water anyway .. i eat 4+ times a day and i wash the plate afterwards ... i wash my hands when i use the bathroom .. etc. There is a good height difference between the sink and the hole where water leaves the apartment ... with a small copper tube i could twist it a few times ... creating a big area of cooling ... When my fridge works, it uses about 250W says the killawatt .. in the summer that is quite a lot of heat, if you manage to remove it from the apartment .. Soo, what do you think ?

07-03-13, 09:11 PM	#2
jeff5may Supreme EcoRenovator Join Date: Jan 2010 Location: elizabethtown, ky, USA Posts: 2,431 Thanks: 431 Thanked 619 Times in 517 Posts	Many people have done this. google the term: Greywater heat recovery Most greywater systems are used to preheat the hot water supply line before it gets to the water heater. The idea is to reclaim this wasted heat before it leaves down the drain. Your idea of dumping waste heat into the drain line would also work well. Good luck! BEWARE: This thought process leads to more energy-saving ideas!

07-04-13, 03:44 PM	#3
nexsuperne Helper EcoRenovator Join Date: Feb 2012 Location: 30 miles east of London, UK Posts: 88 Thanks: 12 Thanked 19 Times in 18 Posts	Using the heat from the coils is just how an air to water heat pump works. I have a commercial client that runs huge freezers (the size of a house), initially, all the waste heat was lost to the fresh air outside, until I persuaded him that an ashp to preheat his sterilizer water tank would save a large amount of money. We now have that powered with solar pv, and then an additional array of 600 evacuated tubes to get the sterilizer water tank to 95C. On a sunny day, he can run the plant for nothing!

07-04-13, 07:33 PM	#4
goblinsly Lurking Renovator Join Date: Jul 2013 Location: Slovenia Posts: 17 Thanks: 0 Thanked 1 Time in 1 Post	Great to hear that this ideas actualy work ! For now i am only interested in cooling down the fridge and taking that heat out by using tap water ... right now i dont have the time or finances to use that hot water for anything ... i am using a gas powered furnace that heats water on demand, it doesnt store it. I do know that fridge will use less electricity since it will run cooler and soo the cycles will be shorter but more importaint, during the summer my apartment will be a tiny bit cooler ( not much though ). I do have some ideas for the future ... when i will have the time. Let me just say that i am very glad i found this forum. I have lots of "macgyver" ideas and its good that there is a place where i can verify or debate about them.

07-31-13, 05:36 AM	#5
goblinsly Lurking Renovator Join Date: Jul 2013 Location: Slovenia Posts: 17 Thanks: 0 Thanked 1 Time in 1 Post	If i could just use this topic to ask another thing .... My fridge is working for 30 mins and then resting for 60 mins. I noticed that as soon as the fridge turns off, the fans cool off the coils in a couple of minutes and then keep blowing but all the work goes to waste...soo i am thinking of adding more material and connect it to the coils .. this means there will be more material to be heated in this 30 minutes and therefor the coils will have the lower temperature ... and as the fridge turns off, in those 60 mins it will get cooled down. I am pretty sure this should work because in those 60 mins, the coils always get cooled down to near air temperature. Soo basicly the only thing that matters is making sure that those 30 mins when compressor runs, there is a lot of material absorbing heat and in turn making the gas in pipes cooler ...

07-31-13, 08:17 AM	#6
razor02097 Helper EcoRenovator Join Date: Mar 2013 Location: 245862 Posts: 43 Thanks: 12 Thanked 3 Times in 3 Posts	I assume you have a fridge with the coils underneath? The fan not only helps to move the rest of the heat out from the coils but also keep air flowing around the compressor. Just keep in mind the appliance was manufactured with a certain tolerance in mind for airflow to cool off the coils, as well as the surface area for the coil. By adding material you raise the mass and the ability to absorb heat but also reduce surface area and potentially airflow. This could potentially reduce efficiency.