If your Heat Siphon is running and the air IS COLDER by approximately the amount in the graph below, then that heat is being removed from the air and delvered to your pool water. LET IT RUN - IF THE AIR GOES BELOW 50°F AT NIGHT it may be shutting off to protect itself from icing and not running long enough even though your pump is running all night.
VERY SMALL AIR TEMPERATURE DIFFERNCE
If the difference in air temperature IS MINIMAL just a few degrees when it should be much more then you could have a small refrigerant leak and still have enough refrigerant to allow it to run but not enough left to MOVE HEAT in the amount needed. This is unlikely since the normal operation with anything should quickly reduce the pressure below the sensor trip point causing a LO P error on digital units or shutting down on analog units. In this case locating and repairing the leak, then recharge the refrigerant will restore your Heat Siphon to optimum performance.
Below is the normal Heat Siphon Air temperature difference and what affects the value.
The Goodman Graph
One day a new Heat Siphon owner named John Goodman, who lives
in Southern California, e-mailed us asking why his new Heat Siphon didn't seem
to be performing according to the published specifications.
John has a Ph.D. in Physics and the
History of Science & Technology.
Being the very curious individual that he is, John took it upon
himself to try and measure the heat output of his Heat Siphon using a pool thermometer
and recording the pool temperature gain and loss versus time with the unit running
and off and trying to estimate the pool heat loss covered etc.
He reported that when
he first turned his unit on the air temperature was 50° F to 55°F and after running for 6
hours, his 15,000 gallon pool had only gained 3°F from 59°F at 6 PM to 62°F at midnight.
Now doing the math he figured that
raising 125,000 pounds of water by 3°F in 6 hours
amounts to about 62,000 BTU/Hr or only 65% of the rated BTUH heat output for his
Z575HP Heat Siphon.
A few days later, after the air temperature
went up it did reach 85°F, but Dr. Goodman was now on a mission. He even bought an
infrared thermometer to measure the pool temperature more accurately.
He wanted to know how the heat output
and efficiency varied with air temperature and water flow rate.
After several lengthy email exchanges of detailed technical
data, we convinced him that the simplest way to really determine if his Heat Siphon
was working properly would be to measure the amount of COOLING it created while running.
As we explained to him, " that heat must be going somewhere
and the only place it can go is in your pool water".
We told him that, we could specify the actual expected "cooling" difference
between the air out and air in , for his model Heat Siphon, as designed.
. . . cont'd. on right sidebar
IF THE DEW POINT
is ABOVE the AIR OUT TEMPERATURE THEN
AIR OUT is LIMITED TO THE DEW POINT
EXAMPLE: Dew point = 59°F and Goodman graph says Air
Out should be 52°F THEN 59°F WILL BE THE REAL AIR OUT
AND if he measured the same temperature difference, it would
prove that everything was "cool" with his unit.
The only problem was - WE DIDN'T HAVE MODEL SPECIFIC DATA to
provide to Dr. Goodman.
So we made him what we now call - "The Goodman Graph"
- named in his honor since he caused it's creation.
It turns out that Dr. Goodman's pool was actually more like 24,000
gallons and had copper plumbing, both of which would require more heat input than
he calculated originally which explains his initial "puzzlement".
(He is now happy with his unit)
WAIT THERE'S MORE!!
The Leach Corollary:
Just about the time we thought the Goodman Graph had answered
the performance question, a chemical
engineer named David Leach, who also owns a HEAT SIPHON emailed us saying that
the GOODMAN GRAPH ISN'T WORKING.
According to his thermometer in Jacksonville FL the "air in
minus air out" was 7°F and the Goodman Graph shows 12°F for his
model at an air temperature of 70°F . BUT HIS POOL WAS 92°F.
It would seem that his Heat Siphon was really working well
as it could keep his pool 22°F above the air temperature AND it was getting
the heat from the air but why was the temperature drop not 12°F which was about
the amount of cooling that equated to the heating his unit was delivering?
we checked the
weather data for Jacksonville, FL that day the HUMIDITY was very high - above
Once his Heat Siphon cooled the air to the dew point, it began
condensing water out of the air and this "heat of condensation" was providing the
rest of the heat to his pool without lowering the air temperature any further.
Since there is an
infinite supply of moisture in the air, THE DEW POINT TEMPERATURE is
the LOWER LIMIT of Heat Siphon's air cooling - and The Leach Corollary was born:
OUTLET AIR TEMPERATURE
CAN'T GO BELOW THE DEW POINT