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Marmite the Dog

Well, you're the designer. Get on and design it. :P

watterinja

It's already designed... How many kW do you require?

Marmite the Dog

About 60.

watterinja

60kW... What hotel is that for (120+ rooms)?

Marmite the Dog

A ton of heat is 12,000 British thermal units per hour (BTU/h) or 3.5 kilowatts.

OK, well I suppose 120,000 BTUs would do for a house, so 30 to 35k would suffice.

What were you thinking of?

watterinja

So, you've got a house, with 35kW of cooling off the evaporator coil.

Next calculations:
1. Determine the electrical power required (to drive compressor, fans x2);
2. Determine kWh energy usage in one day, month;
3. Determine monthly electricity bill.

Can I be your Bank Manager?

Marmite the Dog

Are you going to do the calculations or am I?

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I will meet the blackness and the blackness will be eternal

blackgang

well I need another ton if thats how you figure it, for the living room as I run this one in the bedroom 24/7 now, so be another 3.5 KW

Norton

Must be where your computer is located! Mine too.

blackgang

Yea, I put one in the bedroom, but I can get no one to come and put in my attic fan as some work needs to be done to do it, so I am going to put another 12000 BTU in the living room.

A couple of years ago I did start the hot season running 37000 BTU of aircons for the first month, and what had been 4500 to 5000 a month before was now 7500 a month so I quit that shit and ran only a 12 in the bedroom at night and only about 4 hours a day on the big one in the kitchen/dining room.

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Did you know the average male is 6 inches long, and the average female is 8 inches deep? So in New York City alone there is over 3 miles of unused pussy!

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Marmite the Dog

A friend of mine has a couple of fans built into holes in his bedroom walls which he leaves running all day and says that they negate the need to run the AC.

I was thinking of trying something similar, but finding the right fan might be a problem, as I wanted to try mounting one on my security bars, so it would have to be thin like a car fan. If I bought a car fan, would it be easy to find a 12v transformer. I assume it would as they are used for low voltage lighting aren't they?

watterinja

The title of this thread is 'Passive House Cooling'.

Fans, a/c, are 'active coolers'. You will need to broaden your views MM.

(Btw, thanks for removing my previous post. Don't forget the COP, if you're going to compute your a/c electricity bill)

garyk

I have just read some of the postings here.
WOW,,,, I do not want a heated discussion here but this is what i think.

I worked on many geothermal systems in the past... But the ones i worked on all had problems... (The Same Problem) Not enough holes in the ground. Simply could not transfer enough heat into the ground or what ever they were using to transfer. (Swimming pool, Lake, what ever.) Cost cutting on holes in the ground or poor engineering to begin with. Who knowes.... EXPENSIVE

Every one knowes it is cheaper to heat water or air or whatever with a heat pump. With high effiency compressors and increased condenser area,,, very good. I see now two speed and even variable speed compressors now. For up to 20 SEER and up. COP of 9 and up.... WOW

The bottom line is cost ,,, cost ,,,, COST of installing and maintaining.

In my opinion. Large to medium size buildings of new construction is a good choice for high tech engineering for cost savings. ( DDC control, geothermal or water source pumps... on and on.....)

In Tropical locations. I personally see no need for high tech high cost equipment for residential applications.

I think insulation, insulation, insulation on existing houses, Then run a quick load and install a medium effiency air cond. in your home. Cost wise you will be way ahead...
Hot water.... Your in the tropics.. sun abounds... USE IT.... If possible.... If not go with a heater on the wall.

KISS , Keep it simple stuid. My motto now in life...

Go, GREEN

watterinja

A few corrections.

1. COP
A COP at 50'C refrigerant saturation temperature, of 5 is thermodynamically possible - COP,hp ~ 9 is impossible at mid-range.

COP,hp ~ 8.62 at 30'C Tsat i.e. startup conditions.

These figures are using a scroll compressor, with high isentropic efficiency.

2. Cost
The purchase cost is the main obstacle, after that, the electrical cost is negligible. Maintenance of a well-manufactured AWHP is almost negligible. The system should have less maintenance cost than a conventional a/c system.

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Marmite the Dog

I know, but it didn't seem worth starting another thread.

VocalNeal

Interesting thread.

I was thinking of incorporating water pipes in the walls (I think covered in a different thread) and running the water through a cooling tower. These are relatively cheap here and available in small sizes and used. Best one could hope for though is about 27 C (lower up north) but that is better than 34C.

It is a question of closed or open plan housing. Shade and breeze is the answer.

On the swamp cooler theme Saijo Denki has a line of A/C units with "Swamp coolers" mounted on them. These both cool the incoming air to the compressor and filter out the airborne contaminates. Downside the filter units will have to be changed occasionally. I am investigating retro fit to my two biggest units.
Also have to run a water supply to the trough.
I tried spraying water into my compressors but could never get the correct spray pattern so gave up.

My other hair brained scheme was to drip water hydroponics style onto the roof, theory being that latent heat of vapourization is quite high and it would draw off the heat. I have seen the running water type in Isaan but i would think that uses too much water. Maybe a conbination of the running water and cooling tower.
Also thinking about making a cooling tower. I need a Lao-type laboratory!!

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DrAndy

no, it is about cooling

garyk

I stand corrected I was thinking of HSPF on a pump for heating and cooling. Which can go about 9.0. Heating season performance factor. And a lot of variables are here.. I am old so there...

I am a little confused if i remember correctly COP is KW supplyed as output. Compared to the KW input

For instance say your system is running 3.5 COP Then for each KW input you are producing 3.5KW output . (4.5KW output - 1KW work) = 3.5KW actual out put. (I THINK) If so it is no brainer to see how a pump for heating water or anything is cheaper than electric.

Also if i remember 1KW = apprx. 18K BTU -19K BTU. I will use 18,500 BTU / KW

If i am thinking about this right... ( please tell me if correct. and correct me )
If your unit is running say COP 3.5 then a 1KW input would deliver 64,750K BTU or 3.5KW. or about a 18,500 btu compressor

Question:

What is the COP of your unit.
How much in dollars is say a 3.5 KW output system or how do you typically size a house with your unit? Since you are storing the water for later use i assume. Lets say for a 30 gal. storage capacity. Again i am only guessing...

Send me a link to your site and specs.

Then i will decide....

Since i know nothing about heat pump water heaters i am interested.....

watterinja

^ Hi Garyk,

PM me, & we can talk further.

COP,hp at 3.5 is on the low side of my designs, I typically expect more than 4 from a poor design & 5 from a decent optimised design.

So, you pay $1 into the machine & get $5 of heat energy - for a good machine. Like printing money.

garyk

Sorry 1KW = 3414BTU So a unit of COP 3.5 at 1KW= 11,949 BTU
or a 3,414 btu compressor... which is nothing....

Say input 5 KW at COP 3.5 = 59,745 BTU or a 17,070 BTU compressor.
This is better.... makkkkkkkk... OK Now i am interested more....