index index
RV Maintenance
Thermal Efficiency 2

Closet-2-Unfin.jpg, 19 kB
Here is a "half height" closet.
Shown is the back side insulated.
The right side needs to be insulated too: It goes to the outside.
Also, I will insulate behind these drawers, and to the right side of these drawers, down below. Do not insulate the left side wall near the bed.
Closet2P6.jpg, 26 kB
Full height closet:
Insulate back side, and top. Do not insulate the sides to left and right, these sides do not go to outside, and will serve as heat reservoirs.
IR-BlackPaper.jpg, 18 kB
Preparing to remove register; and by hand hold black cardboard in middle of air stream. Then measure heat with IR thermometer. This is the first of three registers. You must read upstream as close to the furnace as possible. This will measure the furnace output temperature.

The same method is used at the air intake of the furnace, by holding the cardboard a few inches away from the input.

We will see the air temperature rise between input and output.

Although handy, this thermometer is very inaccurate.
Thermometer-Orchard.jpg, 14 kB
This my "orchard" thermometer.
Still fairly handy, and very accurate.
I can read to a quarter of a degree!

RULERMAR.GIF, 1 kB Made insulation improvements. Now, I will make another run of temperature measurements. The outside temperature is 18.9F degrees, well below freezing. And the inside temperature is just above freezing at 35.6 degrees.
For unattended operation this is a perfect inside temperature.
The water filters and lines are heated during the day with the solar panels. They are 36.5F and 36.8F degrees.

But I am out here in the RV now, and I am going to occupy the RV because I need some readings. My target inside temperature will be about 70F degrees. The larger the differance between inside and outside, the more accurate the R-Value determination.
INSS=inside RV temperature, half way up a wall,
INT=Furnace intake temp,
OUP=Furnace output temp in the ductwork,
OUTS=outside temperature, outside ambiant air
ORCH=orchard thermometer located near the furnace input air
STATONN="Thermostat contacts are closed."

07:50:00 35.6INSS                          18.9OUTS
07:51  18.8OUTS 36.5WAT1 36.8WAT2  36.5ORC 32.6MAG 34.7WALLR 34.1WALLB 32.0WALLL 31.7Comm
Begin raising inside temperature...                          
07:57:30                     7.1A 11.92V               STATONN
07:59    38.2INSS 42INT   116  OUP                           
08:02:15          43.1INT 150.2OUP 38.0 ORCH                 
08:03:12 50.7INSS 44.6INT 156.2OUP 38.9 ORCH                 
08:05:00 53.9INSS 47.6INT 167.0OUP 40.0 ORCH 19.4OUTS        
08:15:19 59.2INSS 59.3INT 166.4OUP 47.0 ORCH                 
08:30    69.0INSS                                      STATOFF
08:31:32 68.7INSS                                            
08:32:26                                      20.4OUTS ALL-OFF
08:34:38 61.6INSS         109.1OUP                     STATONN 
08:35:46 62.5INSS         126  OUP                           
08:38:26          65  INT 154  OUP 57  ORCH                  
08:43:01 66.8INS                                       ALL-OFF
08:45:49 62.1INS  65.9INT  99  OUP 58.1 ORCH           STATONN 
08:51:22 68.4INS                                       ALL-OFF
08:54:28                                               STATONN
08:54:43                                               FIRE-UP
08:59:30 69.1INS                              23.3OUTS ALL-OFF
09:03:42 63.0INS            99.6OUP                    STATONN
09:06:26           67.3INT 152.6OUP                          
09:07:00 71.4INS           156.0OUP                    STATOFF
09:08:23           69.4INT 109  OUP  60 ORCH           ALL-OFF
09:13:29 63.3INS                                       STATONN

The temperature is above freezing now and increasing rapidly. All of this measuring is for nothing! Neather the outside nor the inside temperature is stable. I will have to try another day...
Another run, another day...
12:32:50 75.5 53.0
12:33:30 73.8 53.0
12:36:48 69.7
12:51:50 67.8 53.8
13:08:40 67.2 54.5

Clear Lake readings
05:03:    69.2 Inside 28.7 Outside  furnace off
05:10:53  64.7 Inside               furnace onn 7.883 off
05:18     68.7 Inside 28.7 Outside  furnace off 7.116 onn
05:26:00  66.2 Inside               furnace onn 8.000 off
05:32:00  68.9 Inside               furnace off 6.000 onn
05:40:16  64.7 Inside               furnace onn 8.266 off
05:46:55  71.1 Inside               furnace off 6.650 onn
05:56:06  65.1 Inside               furnace onn 9.183 off
06:02:48  71.7 Inside 28.0 Outside  furnace off 6.700 onn
06:12:28  65.1 Inside 28.7 Outside  furnace onn 9.666 off
06:19:19  69.8 Inside 28.2 Outside  furnace off 6.850 onn
Onn times are increasing because the voltage at the blower is decreasing. It is less efficient. The off times are increasing as inside material comes up to temperature. Final off time is difficult to estimate. It is approaching asymtotically a value. Final off time should be about 13 minutes and final onn times at about 6.9 minutes.

Eq-ValClearLake.gif, 5 kB
Heat on is 6.9-(1.5min + 22sec)=5.03minutes.
Onn Duty cycle is 0.251 factor, which should produce 3521 BTU/Hr.
Average inside temperature is 67.5F degrees, Difference is 39F degrees.
R-value is 6.7

Eq-DecayFtBrag.gif, 8 kB
06:21:30  68.2 Inside             
06:35.20  64.1 Inside             
07:11:00  59.0 Inside 27.3 Outside
07:38:12  56.2 Inside 27.0 Outside
07:42:48  56.0 Inside 27.0 Outside
07:43  end 11.86v
The k value is much better than this (lower value) because the inside "stuff" has not been fully warmed up yet, and is unfairly contributing to the heat loss. (My battery is low too, I will try again another day.)
Eq-TempDecayVan2.gif, 10 kB
Here is my van...
And I was sure wrong about it!

For 49 minutes I witnessed the temperature drop from 77 to 61 degrees F. The rain has an unfair advantage when it runs over glass and other surfaces, of increasing heat loss by contact conduction.
I was thinking that there is no way it can compare to my RV. Wrong!

Insulating qualities are not as good as my RV. I know that for a fact. The larger the negative number (exponent kt) the worse is the insulation. But that exponent "kt" also contains a hidden variable: the energy reserve.

Evidently, there are huge energy reserves from the hot engine which is inside and just under the "dog house". The engine is massive steel, and hot at 160F degrees plus! Also a warm floor, the warmth of which you can feel with your hand; carpets, upholstery, and two heaters cores, one front and one back. And both hot. Clearly the insulating qualities are not better than the RV, but the heat reserves are huge and compensate well.