System and Method for Collecting and Utilizing Heat from an Effluent Disposal System

Abstract

A system and method for collecting heat generated by the microbial action in a septic system effluent disposal area that is then transferred to a building structure where it may provide, for example, the temperature differential for a heat exchanger in a heat pump, thereby being the energy source for heating and cooling buildings.

Claims

1. An effluent disposal system that receives effluent from a plumbing system and that is adapted to collect heat from the effluent, the effluent disposal system comprising: A thermal transfer layer horizontally positioned between an effluent disposal area and a finish layer; and Wherein the thermal transfer layer includes a thermal transfer medium that moves through the thermal transfer layer and absorbs heat from the effluent.

2. The effluent disposal system of claim 1, further including a pump that causes the thermal transfer medium to pass through the thermal transfer layer.

3. The effluent disposal system of claim 1, further including a clean fill layer beneath the thermal transfer layer.

4. The effluent disposal system of claim 1, further including a bottom restrictive layer beneath the thermal transfer layer.

5. The effluent disposal system of claim 1, wherein the thermal transfer medium is water.

6. The effluent disposal system of claim 1, where in the thermal transfer medium is ethanol.

7. The effluent disposal system of claim 1, further including an insulating layer and an air vent.

8. The effluent disposal system of claim 1, wherein the thermal transfer layer is comprised of tubing.

9. The effluent disposal system of claim 8, wherein the tubing is made of high density polyethylene.

10. A heating and cooling system comprising: An effluent disposal system that receives effluent from a plumbing system and that is adapted to collect heat from the effluent, the effluent disposal system including a thermal transfer layer that includes a thermal transfer material; A heat pump system that is connected to the thermal transfer layer; Wherein the thermal transfer material flows through the thermal transfer layer where it absorbs heat from the effluent and passes through the heat pump system where it provides the temperature differential for a heat exchanger in the heat pump system.

11. The heating and cooling system of claim 10, wherein the effluent disposal system includes a finish layer positioned above the thermal transfer layer and an effluent disposal area located beneath the thermal transfer layer and wherein the plumbing system causes the effluent to enter into and pass through the effluent disposal area.

12. The heating and cooling system of claim 10, further including a pump that causes the thermal transfer medium to pass through the thermal transfer layer.

13. The heating and cooling system of claim 10, further including a clean fill layer beneath the thermal transfer layer.

14. The heating and cooling system of claim 10, further including a bottom restrictive layer beneath the thermal transfer layer.

15. The heating and cooling system of claim 10, wherein the thermal transfer medium is water.

16. The heating and cooling system of claim 10, further including an insulating layer and an air vent.

17. The heating and cooling system of claim 10, wherein the thermal transfer layer is comprised of tubing.

18. The heating and cooling system of claim 17, wherein the tubing is made of high density polyethylene.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention is described with reference to the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements. The drawings are not drawn to scale.

[0028] FIG. 1 is a top view of the system according to the invention.

[0029] FIG. 2 is a sectional view of the system showing the layers in the drainage field.

[0030] FIG. 3 is a cross-sectional side view of a building structure showing the plumbing and venting system.

DETAILED DESCRIPTION OF THE INVENTION

[0031] The present invention will now be described more fully in detail with reference to the accompanying drawings, in which the preferred embodiments of the invention are shown. This invention should not, however, be construed as limited to the embodiments set forth herein; rather, they are provided so that this disclosure will be complete and will fully convey the scope of the invention to those skilled in the art.

[0032] FIGS. 1-3 illustrate a heat collecting effluent disposal system 100 (“EDS”) for use in practicing a method of heat collection. The EDS 100 is adapted to collect heat from effluent in an effluent disposal area 30, after which the system 100 may convey that heat to a conventional heat pump H designed for use with any geothermal system for use in providing the heating/cooling requirements for a building structure B.

[0033] More specifically, the heat collecting EDS 100 includes a layer of finish material 10, a layer of thermal transfer material 20, the effluent disposal area (“EDA”) 30, a layer of clean fill 40, and a bottom restrictive layer 50. An insulation layer 60 may be inserted between the finish material 10 and the layer of thermal transfer material 20. There may also be a receiving layer above the restrictive layer.

[0034] To one side of the system 100 is a conventional building B that has conventional plumbing that causes waste to exit the building by a sewer line L and into a septic tank S where the solids are separated from the liquid effluent and the effluent sent out of the tank S and into a distribution box DB for dispersal into the EDA through effluent distribution tubing T. Aerobic microbes require air for proper function. This air is supplied to the EDA through absorption through permeable finish materials covering the EDA and the air that is transported to the EDA through the building plumbing venting BV and plumbing drainage BD, a system that provides additional air to the waste plumbing piping which is continuous to the EDA. An air vent V may be connected to the end of the effluent distribution tubing T for the EDA in the conventional manner, and is likely a required component if a layer of insulation or impermeable finish material is installed.

[0035] The thermal transfer material 20 in the embodiment shown is heat transfer tubing, and in particular liquid heat transfer tubing. For example, tubing made of high density polyethylene (HDPE) is a well suited for the thermal transfer material 20. Other options include tubing made of polyvinylchloride (PVC) or aluminum. The tubing is placed above the EDA in a continuous loop and is a closed system that is connected to a heating and cooling system H that is used with the building B. For example, the tubing may pass through a conventional heat exchanger. The closed system is pre-filled with a transfer medium that is in liquid form, which may simply be water. The length and diameter of the tubing is determined by the size of the field and by the intent of the collection, for example, the thermal requirements of the building to be heated or cooled. As the effluent breaks down and generates relatively consistent level of heat that heat rises and warms the surrounding area. That heat is then absorbed by the thermal transfer medium, and a conventional pump P causes the warmed liquid to heat the refrigerant in the heat exchanger, which then, by virtue of the heat pump system, moves the refrigerant to a compressor which generates additional heat which is then transferred via the refrigerant to the conventional building heating system, either forced air or radiant. If cooling is required, the heated refrigerant is directed to an expansion tank where, when the refrigerant expands, it cools rapidly. That cool energy is transferred to the building cooling system, the same as the transfer of heat. It is likely that some amount of tubing is needed to carry the thermal transfer medium from the EDA to the building B and in such a case closed cell pipe insulation may be applied to the tubing to help retain as much heat as possible as the medium enters the heat pump.

[0036] A standard geothermal heat pump system P, includes: 1) a circulating pump that moves the transfer medium between the EDA and the heat pump system; 2) a heat exchanger that receives the transfer medium energy via a refrigerant in the heat pump system; 3) a circulator pump to cycle the refrigerant to the components; and 4) a compressor that compresses the refrigerant, generating heat that is transferred to a hot air or radiant heat system. If cooling is required, an expansion tank is placed in line after the compressor. When the compressed refrigerant is rapidly allowed to decompress it cools rapidly, the cold is then transferred to an air or radiant system.

[0037] The components of the geothermal system are all interconnected and function at given capacities based on material used and application, as follows: [0038] the transfer medium pump speed is set according to the British thermal unit (“BTU”) transmissivity of the transfer medium (water, ethanol, etc) and the BTU requirements of the structure. This is also impacted by the capacity of the heat exchanger as well as the size of the EDA and the length and material of pipe installed for collection. [0039] the heat exchanger has to be sized to draw the BTU requirement for the structure and have the return flow of the transfer medium still in a fluid form, which is another function of flow rate from the transfer medium pump. If the transfer medium returns to the EDA too cold to support microbial action, a conditioning coil C of piping returning the medium to the EDA is placed in the septic tank, which maintains a temperature at or above the surrounding earth. The length of the conditioning coil is determined by the transmissivity of the transfer medium, the temperature at entry to the septic tank, and desired temperature entering the EDA. The components of the heat exchanger have to be compatible with the transfer medium. [0040] The size of the septic tank above the local required minimums may be affected by the need of preconditioning of the return medium conditioning coil C, if required.

[0041] As noted, water is a common collection medium and if the BTU of heat requirements for the structure match the collection capacity of the tubing installed and the cooled water from the heat exchanger recirculating back to the EDA for energy collection may be kept above freezing, then water is a good choice for the collection medium. If a well or horizontal system is designed, more well depth or more land excavated to provide more collection tubing interface with the heat source, for example ground water or earth at 4 foot or greater depth, may be added for more BTU's to be transferred without the heat pump system having to draw additional energy from the transfer medium to supply the BTU requirement for the structure to the point that the medium freezes. Depending on the type of EDA, the tubing requirement for 12,000 BTU's (one ton, in heating, ventilation, and air condition (“HVAC”) terms) is between 475 and 600 feet of 1″ HDPE pipe when using water as the medium.

[0042] Several other transfer mediums may also be used, though many come with toxic potential or flow restrictions at various pump velocities and/or temperatures. Ethanol is a suitable alternative in that energy at the exchanger may be extracted down to 15 degrees Fahrenheit (“F”) and still flow back to the EDA for collection. Microbes in the EDA are unlikely to survive with return medium liquid entering the system at 15 degrees F. Creating a coil C of return medium piping of sufficient length placed inside the septic tank, which functions at or above surrounding ground temperatures, is able to precondition the return medium, ethanol in this case, to a temperature not detrimental to the microbial action of the EDA.

[0043] The layer of insulating material 60 may also be provided to helps contain heat in around the thermal transfer materials and maintains a temperature range in the EDS that is conducive to microbial action. The specific insulation material and the associated insulating value are determined by the ambient temperature range in the geographic location. For example, closed cell sheets that cover most or all of the transfer layer 20 is often appropriate. This allows the EDS to function as designed with no deleterious impact from the collection of the rising heat from the EDS by the transfer tubing.

[0044] The finish material 10 is a conventional material used for such purposes, such as topsoil, paving or other suitable surface.

[0045] As previously noted, the thermal transfer material 20 is connected to a building, where it may be used with a conventional heat pump system. In this example, the warmed medium provides the temperature differential for the heat exchanger to transfer the heat to a refrigerant, which is then piped through the remainder of the conventional heat pump system.

[0046] To construct the EDS 100 the system components are designed so that the EDA and other components of the septic system are installed as is appropriate for site conditions. The EDA is built to the point of effluent conducting tubing or distribution matrix materials, as discussed earlier, and the requisite sand or stone are in place. The tubing of choice is placed per design. For example, the tubing may be High Density Polyethylene tubing having approximately a 1 inch diameter. If an insulating material is required over the tubing it is installed over the final coarse of sand or hay depending on the type of EDA. If a preconditioning coil on the return line to the EDA for the transfer medium is required it is placed in the septic tank and connected to the return line incoming and outgoing the tank. Septic tank manufacturers should be consulted for coordination of placement, entrance and exit of the coil. All HDPE tubing and connections should have minimum 160 pounds per square inch (PSI) break strength. Supply tubing from the EDA to the heat exchanger should be insulated with minimum of 2 inch closed cell pipe insulation or equivalent. The lines are connected to the heat exchanger interface, and the heat pump components are adjusted to design specification. The transfer medium lines are then charged with appropriate material. Slight adjustments may be needed based on various local, state and plumbing codes.

[0047] It is understood that the embodiments described herein are merely illustrative of the present invention. Variations in the construction of the system and/or steps in the method may be contemplated by one skilled in the art without limiting the intended scope of the invention herein disclosed and as defined by the following claims.