An unusual home heating strategy

mwilliamshs

New member, first post. I did some searching and didn't turn anything up. If this should be somewhere else or posted differently I'm all ears.

I live in a 4th floor apartment and domestic hot water is supplied by a natural gas boiler the operating cost of which is divided amongst all residents of the complex so I pay very very little for hot water. Hot by the way, means about 145° at the tap. Haven't measured this precisely or in winter but it's hotter than it should be for bathing kids or the elderly in my opinion. (Checked water temp and got 147° at the tap. Guessing it would drop a bit in winter, remains to be seen)

Electricity on the other hand, is billed to me directly and is my highest utility 12 months of the year due to having only electric heat.

My thought is to harness the power of my hot water to heat, at least partially, my home. I tried this with some success last winter. I filled my bathtub with hot water at 8:30am each morning before leaving for class and drained then refilled it again at 7pm and again at midnight. This volume of hot water was plenty to keep my 1,200 sq. ft apartment over 65° a lot of the time. I didn't track outdoor-indoor temps but on mild days, I didn't even bother with the 7pm refill. On the coldest days, it stands to reason this strategy reduced my dependence on electric heat but I didn't quantify the reduction.

So here's my idea: use the hot water feed normally used for the washing machine to fill an insulated tank (ice chest probably) and circulate that through an automotive radiator or heater core and force air over that to heat the apartment.

Currently I think I'll use a watering trough float valve for livestock to fill the cooler, since it fits standard water hose fittings just like the washing machine hoses. I think I'll use a harbor freight fountain pump for circulation. Might use their 12v pump with water hose fittings instead for more gpm and ease of use of the heater in event of power failure (when my electric furnace is useless). Might also use thermosiphon for circulation but that complicates packaging. I think I'll either use a junkyard sourced heater core or radiator, whichever works better at getting the most heat out of the water and into the air for testing then swap in a new part for cleanliness of the used water. I think I'll use a mechanical thermostat with built-in contacts for switching the pump and fan on and off, just for simplicity. If I use a radiator I think thermo-siphon becomes easier due to larger hose diameters. I think the twin window fan I use spring and fall would work well for a radiator, and it has a built-in thermostat that seems to work well, but I doubt its range extends far enough below 70° to be practical. (Checked, I was right. Cranked all the way down is about 70° and it runs on temp rise, not fall)

Here's my current hang up: how to dump the cold water? I plan to dump it either into the washing machine itself or down its drain pipe in the wall. But how? Thermostatic dump valves are a fruitless search. Automotive thermostats open on rising temperature, not falling. All I've got for now is the idea of a second thermostat to trigger a second pump to pump cold water out, which would lower the float, and let hot water in. I'm hoping there's a simple, cheap option I just haven't found.

I'm open to suggestions but as this project is a cost cutting one, it must remain affordable. Target price for the whole project is under $200 retail.

A second temperature control strategy I'm considering is a tempering valve with tank water on one input and fresh hot on the other, output to the tank or the radiator, whichever works best. This could use an overflow style drain but I can't figure how to prevent it from running constantly. Maybe plumb it between the pump and the core so it'd only let in fresh hot as needed? I think the pressures involved there become problematic for an affordable pump without adding a pressure regulator and/or check valve(s). Problem with an overflow drain is it lets out the hottest water first, which is inefficient.

Gordy

So your excess hw usage, and savings in heating the other tenants pay for....That's green. Is your heating system broke? If the domestic hot water is above 120 at the faucet the owner would be very wise to fix, or install a tempering valve before they get a lawsuit.

mwilliamshs

Hatterasguy, Wife?


I'm single. One reason for using the washing machine is the unit could be easily hidden by closing the laundry room doors.

Gordy, no the furnace works fine. I'm the broke one. I concur on the liability of the hot water but I've been here 2 years and it hasn't changed. The complex houses about 1,200 people and was built in 1990. They remodel and update often, things are very nice. Not cheap, but a very pleasant place to live with garages available which are uncommon in my area and a security must-have for motorcycle riders like me.

Jamie Hall

Um... a minor ethical question? All of the owners pay for the hot water... but each pays for the electric heat individually? And you wish to use your fellow tenants' hot water to heat your apartment and reduce your electric bill? Honestly, my friend, I'm not sure about that -- regardless of whether it would work or not.

mwilliamshs

Actually the ethical question was mine too when a couple neighbors gave ME the 'bathtub full of hot water' idea. Apparently almost everyone here does that so until I got clued in (after my first winter here) I was paying for that, for all of them. My water bill is mine alone, only the gas for the boiler is a shared expense and that topped out at $12/month last winter.

Ethics aside, view it as an engineering exercise that may not even get built.

ratio

Once through & dump? No pump required, thermostat opens a water valve, throttle the water through the system, then down the drain?

mwilliamshs

Once through and dump would waste a LOT of water. My hope is that if the quantity of water used in a day works out I could capture it in the washing machine and use it for a load of laundry when it gets full, if that happens after I get home from classes. Not sure how to prevent an overflow of the washer, maybe it's equipped to do that automatically? If I'm dumping at 100° (no idea of dump temp yet) it would be fine for a load of wash as I normally wash with cold unless things are really soiled. (Likely a further nod to equality with my neighbors btw, not to mention that I recycle and thus save them $ on garbage, a shared expense) Remember, I pay my own water bill so waste of any kind isn't my goal.

Gordy

We use to put ice with a keg of beer in the bath tub when I was in school. Nobody cared how cold the apartment was. Invite friends the human body gives up 500 Btus. Invite 10 people, and no problem warming the place up. Pass the hat for the beer.

mwilliamshs

Now there's an idea!

A keg of beer, michelob ultra for me but they're all similar $, is $108 + tax locally and lasts just over a night with just 5 of my friends (each of us having about 25 drinks, 12oz each). Usually gets us through Saturday afternoon and Sunday evening during football season but we supplement with liquor for celebrations. Add ice and cups and you're over $125, DEEP into my project budget. I actually have a kegerator (no ice, but more electricity) down in the garage but since, as I mentioned, I live on the 4th floor, just getting the keg up here takes a few of us. (No elevator) Add the keg deposit for it getting dropped on the stairs (barely dented the rim) and a $25 noise complaint and *poof* the money's spent and I'm still cold. This is the voice of experience speaking.

JUGHNE

Your single apartment water usage is metered for you to pay?
How do they meter the hot water that goes thru a common water heater?
I wouldn't think a single apartment would use enough water for management to justify metering the flow.

Having been on some disaster planning groups, (including the proposed end of the world Y2K event). A scenario I thought of for my mother who lived in an apartment complex at the time was this: Power would be out.....NG still on.....Water heaters still firing......so connect 50-100 garden hose to hot water......run the hose around on the floor.....drain the water into the tub. You would only need a small flow to keep the hose hot.
Redneck "Onfloor" radiant heating!

However, you are not paying your fair share.....the downfall of many a communal living attempts, including the Amana's and the original Pilgrims.........I used to figure out many ways to beat "The Man" and eventually became "The Man" myself and would eventually evict you. (I'm one of those guys as old as dirt)

mwilliamshs

Anybody have experience with thermostatic radiator valves? Everything I find is from the UK. I think one of those and a pump run by a pressure sensor (rv water pump type) would do well here. Fill with a float valve via washer supply. Trigger the fan by the pump and all that's left is the drain...too bad I can't find a TRV that works in reverse, could tee that in before the radiator, plumbed to the washer drain and be done.

mwilliamshs

Maybe just use a timer to pump out cool water? Would take some experimentation and be less efficient.


My goal here is not to entirely heat my house with hot water but reduce my reliance on the furnace and have a viable backup for ice storms. Set the furnace to 60° and maybe have it kick on once during the day (more at night obviously) instead of once an hour.

mwilliamshs

Any ideas on optimum dump temperature? Guess I'll look into cycle settings for home-heating hot-water-boilers.

Gordy

:disclaimer: the following is considered unethical, and is for theoretical, and concept purposes. Actually implementation into a working system is NOT recommended do to system failure possibilities that could lead to structural damage of the dwelling, and imprisonment, or eviction.

A typical 30"x50" bath tub holds 35-50 gallons of water. It has a safety feature (over flow drain). If you serpentine garden hose about the apartment 200' with one end hooked to the Dhw, and the other end of the hose with a valve on it going into the tub (dump zone). Radiant heat emitter.

If you allow .15 through the hose that gives 5.5 hours before over flow is breached. The tub still heats the apartment with any residual btus left. The water then can be used for flushing toilet approx 20 times, washing clothes 2 loads of initial fill, watering plants, run through Britta for consumption in beverages, making ice for beer keg, or mixers, or cold bath.

Invite the tenants over to engage in the usage of the excess water production, and marvel at your newly implemented heating system spawned by their crude idea. Even invite the land lord over to show him a method for emergency heat in case of that ice storm.

Gordy

Or you could put in a request to move into a second, or third floor apartment that has a smaller heat loss.......

mwilliamshs

Gonna repeat the bit about hiding the unit just by closing the wash room doors without creating a tripping hazard or something I'd have to explain to guests shocked by seeing a garden hose strewn about my home.

I actually have an energy benefit from living on the 4th floor 3 seasons of the year thanks to being above the surrounding buildings and having cross-flow ventilation, in from my shaded balcony and out through my bedroom windows.

ratio

If you flowed through an automotive radiator, I bet you could get a 50-60° ∆T with minimum flow. A fan might even be to much, maybe lay the resistor on its side & let gravity do it's thing with the hot air.

In my imagination, it's on the order of a leaky toilet. Simple, cheap, a lot fewer failure modes.

Answerman

So you want to waste a bunch of water (that as Jughne pointed out, you're probably not metered for), and make your neighbors pay for most of the the heating cost you're offsetting, as well as the excess water..
This seems blatantly unethical. Even if some of your neighbors are doing the same thing, that doesn't make it right. If every single resident in the building was doing it, or said they were okay with with you doing this for some reason, that would be a different story.

There are other things you can do to reduce your heating bill without cheating your neighbors. If you haven't already, you can start by air-sealing (i.e. caulking gaps and penetrations) as much as possible and make sure your windows are fully closed and locked in order to reduce heat loss. Closing window curtains at night will make the room feel more comfortable, especially if you don't have low-e windows, which may allow you to lower the temperature (open the curtains in the day for solar gain). You can also use a humidifier so that you're apartment is comfortable at a slightly lower temperature (higher humidity = lower evaporative heat loss), and maybe use electric space heaters (if you don't have individual heating zones) so you don't have to heat your whole apartment as much.

I would suggest looking into installing a mini-split heat pump, with the outdoor unit installed on your balcony, but you don't want to spend money, and your landlord has little incentive to share the cost since they're not paying the heating bill..

hot_rod

You sound like a prime candidate for a tiny house Find or build a structure that matches your lifestyle, and your budget.

Alan (California Radiant) Forbes

You could use an aquastat (Honeywell L6006C 1018) with a remote sensor in the water to turn on a pump to dispose of the water. Set the temperature to 100° and wire it to "make" on "temperature drop"; wire it in series with the pump. The only problem is that it would continue pumping when the reservoir was empty, only stopping when refreshed with new, hot water.

Jury-rigged, MacGyver.............However you spell it, it sounds like a fun engineering project that would best be done in a garage where it wouldn't cause any damage, NOT in your apartment.

Get a girl (or boy, whatever your preference) to keep you warm.

Tinman

I've never seen more "off topic" hits by one person on one thread.

Ever.

Please give me one.

Gordy

Someone still wants Bernie to get free stuff.....

Tinman

Sure. Erin may drop me down to a half star by day's end but that's ok. I can take a punch.

Tinman

I might feel like Bender in The Breakfast Club if I get too many though.

Zman

@mwilliamshs

If you take a 40 gallon tub and fill with 147 degree water. Let it cool to 67 degrees. That will release 666 BTU each time you do it.
Depending on your rate that would save you about 3 cents in electricity every time you do it.

To give you a perspective, if you didn't try to rip off your neighbors and you invited a couple over for a game of cards. Those people would release about 1,100 Btu's every hour they can stand you.

You are probably better off filling the tub....

You can only do one, I would recommend a "flag" or "disagree".

delta T

26,656 BTU. 8.33 lb/gallon not 8.3 Lets get the numbers right here....



OP, you are on forum full of some of the best heating professionals in the country, asking them to design something that is frankly not worth it. My gut feeling is that you could spend your $200 on caulking and weatherproofing and save more on your heating bill while NOT screwing your neighbors on the hot water bill.

just my .02

JUGHNE

That 200 is less than 2 kegs of beer.

Zman

Hatterasguy said:

Zman said:

@mwilliamshs

If you take a 40 gallon tub and fill with 147 degree water. Let it cool to 67 degrees. That will release 666 BTU each time you do it.
Depending on your rate that would save you about 10 cents in electricity every time you do it.

26,560 BTU................a little over $1.00.

That was my bad, thanks for the correction. Must have been the late night....

Now that the "offtopic" OP is gone ( he won't understand this anyway).

The way to do this is to pull the hot water out of the hot side then run it though an oversized fc and stuff it back into the buildings recirc line. If you had to you could cool it way down and put it into the cold side.

I wouldn't, but it would be pretty simple...

mwilliamshs

JUGHNE said:

That 200 is less than 2 kegs of beer.

So clever. So true. So...what's your point?

mwilliamshs

Zman said:

Hatterasguy said:

Zman said:

@mwilliamshs

If you take a 40 gallon tub and fill with 147 degree water. Let it cool to 67 degrees. That will release 666 BTU each time you do it.
Depending on your rate that would save you about 10 cents in electricity every time you do it.

26,560 BTU................a little over $1.00.

That was my bad, thanks for the correction. Must have been the late night....

Now that the "offtopic" OP is gone ( he won't understand this anyway).

The way to do this is to pull the hot water out of the hot side then run it though an oversized fc and stuff it back into the buildings recirc line. If you had to you could cool it way down and put it into the cold side.

I wouldn't, but it would be pretty simple...

Building has no recirc line. Wish it did. Took forever to get hot water in the further building in winter. I moved next door to the boiler building last year. Huge improvement.

How do you know what I do or don't understand btw?

John Mills_5

JUGHNE said:

Your single apartment water usage is metered for you to pay?
How do they meter the hot water that goes thru a common water heater?

I'm still trying to figure that one out too!