Home cooling cycle
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The heart of the “New Home Cooling Cycle” is a concrete heat exchanger located under the home. The heat exchanger is constructed of concrete and PVC piping. There are two flow passes. Each is ninety degrees from the other. On a hot sunny day, heat absorbed by air inside the home is routed through one pass of the heat exchanger where the heat is removed by absorption into the concrete, thus removing heat from the home. Air is circulated using a small electric blower. Air leaving the heat exchanger is cool and is returned to the home ready to absorb heat again. The recycled air absorbs additional heat and the cycle is repeated through the heat exchanger. Regeneration of the heat exchanger is accomplished at night. Cool night air is blown, using a small electric blower, through the heat exchanger second pass, ninety degrees to the absorbing pass. This cooling air absorbs heat from the heat exchanger and exhausts it back to the night air. The two heat exchanger passes are totally isolated to prevent moisture from entering the house circuit. This same cycle is used during winter. On a sunny winter day, solar heat and heat from a wood burning fireplace is absorbed by air inside the home and is routed through the heat exchanger as in the summer cooling cycle. Heat is removed and stored in the heat exchanger and cooled air is returned to the home where the cycle repeats. At night, heat stored in the heat exchanger is routed into the home. During winter, there is no regeneration required for the heat exchanger. Usage of refrigerated air conditioning is radically reduced. In some United States climates, it may be possible to eliminate refrigerated air conditioning.

Aubin, Douglas Edward (Gonzales, TX, US)
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Publication Date:
Filing Date:
Primary Class:
Other Classes:
62/437, 165/47
International Classes:
F24F5/00; (IPC1-7): F24H3/00; F25D23/12; F25D11/00
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Primary Examiner:
Attorney, Agent or Firm:
Douglas E. Aubin (Gonzales, TX, US)
1. I claim the invention of a home cooling cycle that utilizes a concrete mass and blower located under the home and separate from the home:

2. I claim the invention of a concrete heat exchanger that is used for heat absorption and regeneration of the above concrete mass.



I have no knowledge of any related applications.


The invention submitted in this application is not federally sponsored.




Several years ago, my youngest son and I built a Passive Solar Energy home in San Marcos, Texas. The wintertime benefits of this type of design are well documented in numerous books and journals. We were also interested in the home's behavior during summertime. Of particular interest was the floor mass which was Saltillo tile on top of a concrete slab. During a June 100° F. day, with the home closed up and no air conditioning operating, we recorded hourly readings of interior air temperature, from 6 AM to 8 PM. Four thermometers were used. THE AIR TEMPERATURE INCREASED 10° F., from 70° F. to 80° F. We were amazed. However, this is not new technology; it is referenced in many books and periodicals. But this knowledge opened the door for the attached invention. We then operated the air conditioning system, from 8 PM to 6 AM the next day, to exhaust the heat from the house and repeated the test procedure two more days. Results were the same.

Calculation of what happened to the heat entering the house are simple and are shown at the bottom of this section as (5)a. Total heat entering the house is calculated from the air conditioner electric meter. This total is broken down into interior air heat gain 1% of the total, interior walls and fixtures 26% of the total and the concrete floor mass 73% of the total.

It was not clear to us, at that time, how to gainfully use this knowledge. Most of the house heat gain was trapped in the floor mass and there was no low cost way to exhaust it. The only choices were to operate the air conditioning, only at night, where the night temperatures save a little money or open windows and exhaust the heat using a fan like an attic fan. Most people don't like the night air in their house.

Now the application of this knowledge to successfully and considerably reduce air conditioning costs is presented in this invention.

a. Calculation, Passive Solar Energy Home, San Marcos, Tx.

1.Heat removed in 24 hours = Electric
Meter Reading Difference = 20 KWH
BTUs = KWH × 1000 × SEER
BTUs = 20 × 1000 × 9.29 =
2.Heat Distribution
House Air Heat Gain
Q = W × Cp × ΔT%
Q = 12,648 CF Air × 0.0709 #/CF × 0.25
BTU/#° F. × (80 − 70) =2,242 BTU 1.2
Interior Walls and Fixtures Heat Gain
Q = W × Cp × ΔT
W = 200 Ft of Walls × 2 * × .5
in × Ft/12 in x 8 Ft =133CF
Cabinets, Fixtures,
Doors (estimated) =67CF
* Sheetrock both sides
Q = 200 CF × 30 BTU/CF ° F. × 8° F.
(estimated) =48,000 BTU 25.9
Concrete Pad
Q = W × Cp × ΔT
Q = 750 CF × 144 #/CF × 0.156 BTU/
#° F. × 8° F. (est) =134,784 BTU 72.9
185,026 BTU 100.0


A blower and concrete mass are installed under the home. An air cycle is established from the blower, through the home, through a concrete mass and back to the blower. Heat entering the home, on a summer day, is absorbed into the circulating air and then into the concrete mass which is isolated from the home.

In the evening, the cooling cycle is shut down. Regeneration of the concrete mass is then accomplished through the night hours. Using another blower, night air is routed through the concrete mass, exhausting trapped heat to night air. During this regeneration period, normal house air conditioning can be operated to set desired inside temperature.

The cooling cycle and the regeneration cycle are completely separate and do not mix. This is done to prevent night moisture from entering the cooling cycle and subsequently the home interior.

This cooling system can be used for any home construction, pier and beam foundation, slab foundation and mobile homes. It is best suited to new construction but in some cases could be retrofitted.

It is also ideally suited to wintertime savings. With the home facing north-south and with adequate south glass, solar heat gain coupled with a wood burning fireplace and the concrete mass, can smooth interior temperatures and reduce heating costs. Solar and fireplace heat are stored in the concrete mass during the day and used during the night.

This new system will utilize a small computer control system so that the homeowner will not be required to constantly monitor.


Drawing (e)1—An elevation drawing of the overall cooling circuit

Drawing (e)2—Floor Plan of sample home Sunpath Two

Drawing (e)3—Sunpath Two heat gain calculation based on Manual J ACCA 1981

Drawing (e)4—Concrete Heat Exchanger

Drawing (e)5—Plan view showing Concrete Heat exchanger location

Drawing (e)6—Concrete Heat Exchanger PVC pipe spacing


This invention proposes a home summer cooling cycle, in addition to the normal refrigerated air conditioning system. The cooling cycle utilizes a separate blower and a concrete mass located under the home between the floor and the ground. This blower and concrete mass are isolated from the home interior by the insulated flooring. The blower distributes air into the home interior using the normal air conditioning ductwork. It is important that this ductwork be located under the ceiling or under the flooring as in mobile homes and not in the attic.

Heat entering the home is absorbed into the air and interior walls and fixtures. Heated interior air is next routed via a filter-grill into the concrete mass area beneath the home. The concrete absorbs heat from the air, the air flows to the blower suction and returns to the home interior. See drawing (e)1. Calculations shown at the end of this section show that house daily interior air temperature should only rise 5° F. above the 7 AM concrete mass temperature. For example, if the 7 AM concrete mass temperature is 70° F., then the home interior should rise to 75° F. by that evening. See calculation (8)a at the end of this section.

In the evening, the cooling cycle is shut down and the normal air conditioning cycle placed in service. The homeowner can set the interior temperature he desires for sleeping. This removes any moisture that has accumulated in the house. What has happened here is that the normal air conditioning has been shutdown all day and is now operating with much cooler outside temperatures. This saves considerable energy and reduces initial investment by requiring a smaller air conditioning system. Some may choose to leave the air conditioning shut down and use ceiling fans for comfort saving additional money.

In the evening, while the cooling cycle is shutdown, heat absorbed in the concrete mass during the day is exhausted to the atmosphere. This is accomplished using a second blower. Night air is blown across and through the concrete mass and exhausted to the night air. The concrete mass is made up of two sections. One is a simple concrete pad and the other is a concrete heat exchanger. The concrete heat exchanger is constructed with PVC pipe and concrete. There are separate and independent crosscurrent paths through the exchanger to allow the cooling air to flow through one path and the night air regeneration air to flow through a path 90 degrees to the cooling flow. See Drawings (e)4 and 5. As seen from the drawings, night air flows across the concrete pad and through the heat exchanger discharging heat to the night air. Likewise, the cooling air flows across the concrete pad and through the heat exchanger to cause heat absorption. The heat exchanger keeps the cooling flow and the regeneration flow separate so that no night moisture enters the cooling circuit. The heat exchanger is designed and located such that plumbing is fully accessible for any needed repairs.

The cooling circuit temperature is dependent on the lowest nighttime temperature. For example, if the lowest nighttime temperature is 73° F., the next evening's temperature should be 78° F. Said another way, the evening temperature should be 5° F. above the lowest previous nighttime temperature.

Calculation (8)b at the end of this section, gives approximate dimensions of the concrete heat exchanger. In the sample case of Sunpath Two, the heat exchanger is designed in two sections.

a. Calculation of Concrete Required for 5° F. Daily Temperature Rise

A sample house was chosen. See Drawing (e)2. Sample house name is “Sunpath Two”.

Heat gain for a 100° F. day was calculated equal to 18,960 BTU/Hr as shown on Drawing (e)3.

Assume 12 hours of 100° F. exposure. 12 Hrs x 18,960 BTU/Hr=227,520 BTU

For 5° F. Air Temperature change:

A. House Air Heat Gain

    • Q=WxCpxAT Q=15,360 CF x 0.0709 #/CF x 0.25 BTU/#° F.×5 IF=1,361 BTU B. Interior Walls and Fixtures Heat Gain Q=WxCpxAT Q=200 CF x 30 BTU/CF° F.×4° F.(assumed temperature approach)=24,000 BTU C. Heat that Concrete Must Absorb Total Heat Gain-House Air Heat Gain-Interior Wall and Fixture Heat Gain=227,520-1,361-24,000=202,159 BTU

Concrete Required for House Air Temperature rise of 5° F. Q=WxCpxAT 202,159 BTU=W x 0.156 BTU/190 ° F.×4° F. (assumes 1° F. approach) W=202,159 /0.156×4 W=323,973 #s of Concrete Therefore, 323,973 #s of concrete are required to maintain Sunpath Two interior air temperature rise at 5° F. on a 100° F. summer day.

b. Concrete Heat Exchanger Size Calculation

Total Concrete (pad and heat exchanger) Required from (8)a, above =323,973 #s Pad =60 Ft x 32 Ft x 5.5 In/12 In/Ft x 144 #/CF=126,720 #s Therefore Heat Exchanger =323,973 #=126,720 #=197,253 #s Assume Heat Exchanger dimensions =14 Ft W x 3 Ft H x 40 Ft L PVC Pipe =2 In Sch 20

See Drawing (e)6 for pipe spacing 3′ x 14′ side pipes =3×(14×12/5-1)=96 pipes 3′ x 40′ side pipes =3×(40×12/5-1)=525 pipes Total Pipe Volume=3×14 side volume+3×40 side volume 3×14 side pipe volume=r (2/12)A214×40×96=77 CF 3×40 side pipe volume=n (2/12)A2/4×14×525=147 CF Total Pipe Volume=224 CF Required Heat Exchanger Concrete =(3′ x 14′ x 40′- Total Pipe Volume)×144 #/CF Required Heat Exchanger Concrete= (1680-224)×144=209,664 #s (close check with 197,254# above)

Use two Heat Exchangers each 3′×14′×20′ under the sample Sunpath Two house.

See drawing (e) 1 and (e)5.