HEAT RECLAMATION APPARATUS AND METHOD
A kitchen heat reclamation apparatus includes a heat producing kitchen apparatus, and a chute positioned near a portion of the heat producing kitchen apparatus that produces heated air. An air handler moves at least a portion of the heated air produced by the heat producing kitchen apparatus along a heated air path that passes through the chute. A heat extractor is associated with the chute. The heat extractor removes heat from the air before exhausting the air to the atmosphere. The heat removed by the heat extractor can be used in other areas of a building or can be used to generate electricity.
This application claims priority to U.S. Provisional Application No. 62/178,299, filed Apr. 7, 2015, and entitled “GREEN HYBRID WATER HEATING SYSTEM,” the disclosure of which is incorporated by reference in its entirety.
TECHNICAL FIELDVarious embodiments described herein relate to an apparatus and a method of heat extraction. More specifically, to an apparatus and method for reclaiming a portion of the heat otherwise considered waste heat and exhausted from a commercial grill, oven, fryer or any appliance that produces waste heat.
BACKGROUNDEnergy costs have risen the years. Along with this rise in costs, there has been a constant drive to save energy in various parts of the world. In addition, producing energy generally produces carbon which is thought to contribute to global warming. Saving energy is also a way to reduce carbon emissions. Simply put, using less energy means reduced carbon footprint for the user.
SUMMARY OF THE INVENTIONThe present invention reclaims the waste heat, before it is exhausted into the atmosphere. In one embodiment, waste heat is reclaimed from a commercial grill, oven, fryer, or any appliance that gives off waste heat in a food service establishment. The reclaimed heat can be used to heat a portion of a building, such as the food service establishment in the cooler months of the year. The reclaimed heat can be used to generate electricity. In one embodiment, the electricity generated is used to drive a pump which in turn compresses a refrigerant as part of a refrigeration cycle. The refrigeration apparatus can be associated with an air conditioner for a building, in one embodiment, or with a cooler, which is common in kitchens in another embodiment.
The embodiments will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which:
In the following paper, numerous specific details are set forth to provide a thorough understanding of the concepts underlying the described embodiments. It will be apparent, however, to one skilled in the art that the described embodiments may be practiced without some or all of these specific details. In other instances, well known process steps have not been described in detail in order to avoid unnecessarily obscuring the underlying concepts.
In another embodiment, the air handler is absent. The hot exhaust air rises from the grill, fryer, or oven top or other apparatus that produces heated air from which heat can be reclaimed. In this embodiment, heated air moves along a heated air path 130 that passes through the chute 120. The heated air path 130 includes an entrance near a front portion of the grill surface 112. A heat extractor 300 is associated with the chute 120. The heat extractor 300, as shown, is within the chute 120. The heat extractor 300 removes heat from the air in the heated air path 130 before exhausting the air to the atmosphere. The heated air in this embodiment is not forced through the path but is moved by convection.
The fluid flow path 320 includes an inlet 326 and an outlet 328. The tubing in a serpentine pattern is between the inlet 326 and the outlet 328. In the embodiment shown, the fluid flow path is formed from straight lengths of tubing 322. The fins 330 are attached or otherwise thermally coupled to the exterior surface of the straight lengths of tubing 322. U-shaped sections of tubing 323 are used to attach the outlet end of one straight length of tubing to an inlet end of another straight length of tubing. In some embodiments, the straight lengths of tubing 322 include turbulators. A turbulator is a device inserted into the tubes of firetube boilers, shell & tube heat exchangers, heat extractors, and other types of heat transfer equipment that helps to increase heat transfer efficiency. The turbulator is the device that turns a laminar flow of fluid in a tube or length of tubing 322 into a turbulent flow. Turbulent flow is desired on parts of heat extractors 300 or heat exchangers since more heat can be transferred to fluids undergoing turbulent flow as compared to laminar flow. As the heat transfer fluid 324 continues to flow through the heat extractor 300, it continues to warm. The heated air associated with the heated air path 130 cools. In other words, the end effect is that the heated air associated with the heated air path 130 cools as it passes through the heat extractor 300, and the fluid 324 flowing through the tubing 322, 323 warms between the time the fluid 324 enters the inlet 326 and exits the heat extractor 300 at the outlet 328.
Put another way, a heat transfer fluid 324, such as water, is moved through the fluid flow path 320 in the heat extractor 300. Heat from the heated air associated with the heated air path 130 (shown in
In one embodiment, the kitchen heat reclamation apparatus and specifically the heat extractor 300 includes an extractor pump 340 for moving the heat transfer fluid 324 through the heat extractor 300. The extractor pump 340 can be used to vary the speed of the fluid 324 as it moves along the fluid path 320 to vary the amount of heat removed from the heated air by the heat extractor 300. If more fluid is moved along the fluid path 320, additional heat can be removed by the extractor 300. Speeding the movement of the fluid 324 could be in response to the fluid having too high a temperature for the fluid 324 in the tubing 322 of the extractor 300 when compared to a threshold temperature. Of course, the speed at which fluid flows along the fluid flow path 320 has limits. The fluid 324 must flow fast enough to take away sufficient heat to avoid overheating. In some instances, the fluid flow must be fast enough to produce turbulent flow of the heat transfer fluid 324. The fluid flow also must be at sufficiently low speeds so as not to produce high pressure in the tubing 322 associated with the fluid flow path 320. Of course, excessive pressure could produce leaks or failure of the tubes or pipes which would be a failure in the heat extractor 300. In one embodiment, sliver solder is used to connect and attach various high pressure tubes and pipes. Silver solder is capable of withstanding higher pressure than other solders. Thus, in the embodiment using silver solder, the system is more resistant to leaks occurring at the connection points in the heat extractor 300.
Of course, there are times when the fluid 324 can overheat. This may be for any number of reasons.
Should the fluid 324 of the flow path 320 overheat, the baffle 420 closes.
The kitchen heat reclamation apparatus 800, in some embodiments, also includes a heat extractor 840. The heat extractor 840 is located in the chute 820. In this embodiment, the inclined surface 822 and the thermoelectric generator 810 can be used to remove a first amount of heat. The heat extractor 840 can be used to extract a second amount of heat. The kitchen heat reclamation apparatus 800, in still other embodiments, has at least a first baffle 850 and a second baffle 852 and an overheat exhaust port 854. An aquastat in the heat extractor can be used to close the first baffle and prevent or substantially lessen an amount of heated air on the heated air path from reaching the heat extractor 840. The thermoelectric generator 810 can also overheat and the second baffle 852 can be used to prevent or substantially lessen the amount of heated air that contacts the inclined surface 822. One or both of the baffles 850,852 can be in the closed position, open position, or in a partially closed position. Heated air can be exhausted through the exhaust port 854 when both the first baffle 850 and the second baffle 852 are closed. A baffle controller 860 receives signals from the thermoelectric generator 810 and the heat extractor 840 and controls the opening and closing of the first baffle 850 and the second baffle 852.
The electricity produced by the thermoelectric generator 810 can be used for any number of purposes. The electricity can be used to power or partially power other appliances in the kitchen or in the building having the kitchen. One possible use is for powering or partially powering a compressor 870 for a refrigeration cycle for a walk-in refrigerator, an air conditioner, other refrigerator, or the like.
The first baffle 850 redirects the heated air produced by the heat producing kitchen apparatus 800 to a position away from the extractor 840 when the temperature of fluid flowing through the extractor 840 is above a threshold temperature. There may also be times when it is desirable to slow or halt heat flow to the thermoelectric generator 810. The second baffle 852 redirects a portion of the heated air produced by the heat producing kitchen apparatus to a position away from the thermoelectric generator 810. The redirected hot air is exhausted to atmosphere, such as through an exhaust hood.
A kitchen heat reclamation apparatus 100 includes a heat producing kitchen apparatus 110, and a chute 120 positioned near a portion of the heat producing kitchen apparatus 110 that produces heated air. As shown in
Advantageously, the system 1100 will provide up to 30 volts of electricity per twelve TEGs to feed into the electric grid of the establishment. The amount of TEG's needed will vary depending on the temperature and size of the appliance they are attached to.
The system 1100 reclaims the waste heat, before it is exhausted into the atmosphere, from but not limited to, a standard commercial grill, oven, fryer, or any appliance that gives off waste heat in a food service or other establishment, and transfers the reclaimed heat to electricity which is stored in a battery, batteries or a battery bank. The electricity runs from the battery, batteries or battery bank through a regulator to an inverter and into the power grid of the establishment, substantially lowering the cost of electricity in the establishment. In another embodiment, the electricity is produced at one or more TEGs. Electrical energy produced at the TEGs is then passed through a regulator, to a battery to an inverter and then to lights or the electrical grid. In still another embodiment, electrical energy produced by the TEGs could be input to a smart inverter and then to either a battery or to the electrical grid.
Experimental Results
A study was conducted of the kitchen heat reclamation apparatus by the University of Minnesota. The results of the testing are as follows:
The kitchen heat reclamation apparatus is a novel device designed to supplement or plumb into a hydronic heating system while also functioning as a kitchen grill. Conceivably, during periods of low use (or high use periods), a portion of the heat energy stored in the grill can be transferred to a hydronic heating system for heating domestic water, heat for the building or both. The novel concept of this design is that grease laden heated air cannot enter into or onto the heat exchanger surfaces. Combustion air for firing the grill enters from beneath and in front of the grill surface. Any excess combustion heated air is then drawn through a heat extractor thereby transferring its heat to a distributed water stream circulating through the system. Any excess, grease laden air from above the grill is not allowed to enter into the heat extractor surfaces which could easily foul the system. The heat extractor, located upright and at the rear of the grill, is encased in aluminum shrouding and is specially designed to take excess combustion air from beneath the grill rather than from the grease laden air migrating above the grill which flows into an exhaust hood system.
4.0 Methods
A kitchen heat reclamation apparatus was delivered to the NRRI in a configuration where a portion of the copper piping network was housed beneath the grill surface just adjacent to the burner flame front. This network beneath the grill then transitioned into a heat exchanger apparatus positioned upright and at the rear of the grill. The heat exchanger was an OEM unit that is typical of a unit heater used to heat buildings with hot water. This configuration would be tested as a benchmark for its ability to raise the temperature of a known mass flow of water. The net temperature rise of water flowing through the kitchen heat reclamation apparatus at a steady-state condition was used as means to test and monitor its performance while striving to maintain a constant grill temperature. The procedure for conducting a test was to turn on the burner to the grill, start the flow of water, and allow it to reach a steady-state operating condition while maintaining a constant grill temperature. The consumption of propane, the temperature at 4 quadrants on the grill, inlet and outlet water temperature, air temperature exiting heat exchanger and water flow rate measurements were taken at 5 minute intervals. The raw data for the initial benchmark testing was recorded. Following the initial benchmark testing, the project team removed the copper piping from beneath the grill. This was done to simplify the installation protocol and OEM manufacturing techniques where all of the heat exchanger surfaces could be positioned at the back of the grill as opposed to an intricate piping network running adjacent with burners housed beneath the grill. The configurations that were tested by the project team are listed in Table 1.
5.0 Results:
The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the invention. Thus, the foregoing descriptions of specific embodiments of the present invention are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings.
The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.
While the embodiments have been described in terms of several particular embodiments, there are alterations, permutations, and equivalents, which fall within the scope of these general concepts. It should also be noted that there are many alternative ways of implementing the methods and apparatuses of the present embodiments. It is therefore intended that the following appended claims be interpreted as including all such alterations, permutations, and equivalents as fall within the true spirit and scope of the described embodiments.
Claims
1. A kitchen heat reclamation apparatus comprising:
- a heat producing kitchen apparatus;
- a chute positioned near a portion of the heat producing kitchen apparatus that produces heated air;
- an air handler for moving at least a portion of the heated air produced by the heat producing kitchen apparatus along a heated air path that passes through the chute; and
- a heat extractor positioned in the chute, the heat extractor removing heat from the air before exhausting the air to the atmosphere.
2. The kitchen heat reclamation apparatus of claim 1 wherein the heat extractor includes a fluid flow path therein, the apparatus further including a heat transfer fluid movable through the fluid flow path in the heat extractor, the heat transfer fluid input to the heat extractor at a first temperature and output from the heat extractor at a second temperature higher than the first temperature.
3. The kitchen heat reclamation apparatus of claim 1 further comprising an extractor pump for moving the heat transfer fluid through the heat extractor.
4. The kitchen heat reclamation apparatus of claim 3 wherein the extractor pump can be used to vary the speed of the fluid to vary the amount of heat removed from the heated air by the heat extractor.
5. The kitchen heat reclamation apparatus of claim 1 further comprising a second fluid flow path in fluid communication with the fluid flow path in the heat extractor, the second fluid flow path delivering fluid to a plenum from where heat is delivered to a building.
6. The kitchen heat reclamation apparatus of claim 5 further comprising a coil positioned in the plenum, the second fluid flow path flowing through the coil in the plenum.
7. The kitchen heat reclamation apparatus of claim 1 further comprising a second fluid flow path in fluid communication with the fluid flow path in the heat extractor, the second fluid flow path delivering fluid to a tank for regulating the heat of the heated fluid, wherein heat from where tank is delivered to an element needing heat.
8. The kitchen heat reclamation apparatus of claim 2 further comprising an aquastat for measuring a temperature of the fluid in flow path of the extractor.
9. The kitchen heat reclamation apparatus of claim 2 further comprising: a baffle that redirects the heated air produced by the heat producing kitchen apparatus to a position outside the chute in response to the aquastat reading a temperature higher than a threshold temperature.
- an aquastat for measuring a temperature of the fluid in flow path of the extractor; and
10. The kitchen heat reclamation apparatus of claim 1 further comprising an electrical generator associated with the heated air path.
11. The kitchen heat reclamation apparatus of claim 1 wherein the electrical generator associated with the heated air path includes a thermal electric generator.
12. The kitchen heat reclamation apparatus of claim 1 further comprising
- an inclined surface associated with the chute; and
- a thermo electric generator attached to the inclined surface, the inclined surface in the heated air pathway, the inclined surface made of a thermally conductive material that transfers heat from the heated air, through the inclined surface, and to the thermo electric generator.
13. The kitchen heat reclamation apparatus of claim 2 further comprising:
- an aquastat for measuring a temperature of the fluid in flow path of the extractor;
- a first baffle that redirects the heated air produced by the heat producing kitchen apparatus to a position away from the extractor when the temperature of fluid flow is above a threshold temperature;
- an inclined surface associated with the chute; and
- a thermo electric generator attached to the inclined surface, the inclined surface in the heated air pathway, the inclined surface made of a thermally conductive material that transfers heat from the heated air, through the inclined surface, and to the thermo electric generator; and
- a second baffle that redirects the heated air produced by the heat producing kitchen apparatus to a position away from the thermo electric generator.
14. Apparatus for recycling heat from a heat producing kitchen apparatus comprising:
- a chute;
- an air handler for moving heated air along a heated air path that passes through the chute;
- a heat extractor associated with the chute, the heat extractor positioned to remove heat from the heated air path; and
- mounting hardware for mounting the chute, air handler and heat extractor to a heat producing kitchen apparatus.
15. The apparatus for recycling heat from a heat producing kitchen apparatus of claim 14 wherein the mounting hardware includes a mounting bracket.
16. The apparatus for recycling heat from a heat producing kitchen apparatus of claim 14 wherein the chute is made of a material that could be used for a back splash of a heat producing kitchen apparatus.
17. The apparatus for recycling heat from a heat producing kitchen apparatus of claim 14 wherein the chute is made of a material that could be used for a back splash of a heat producing kitchen apparatus, the chute further comprising a shelf attached to the chute at a position above the heat producing kitchen apparatus.
18. The apparatus for recycling heat from a heat producing kitchen apparatus of claim 14 wherein the heat extractor includes a fluid flow path through the heat extractor, the fluid flow path including:
- a fluid input; and
- a fluid output.
19. The apparatus for recycling heat from a heat producing kitchen apparatus of claim 18 further including an aquastat for measuring the temperature of the fluid along the fluid flow path through the heat extractor.
20. The apparatus for recycling heat from a heat producing kitchen apparatus of claim 14 wherein the chute includes an inclined surface, the apparatus further comprising a thermal electric generator thermally coupled to the inclined surface.
21. A method of reclaiming heat or recycling heat from a heat producing kitchen appliance comprising:
- directing an air flow over a heat producing portion of the heat producing kitchen appliance to a thermal extraction device; and
- moving a fluid through the thermal extraction device to transfer the heat from the air to the fluid;
- moving the fluid to another location where the heat is extracted; and
- exhausting the air which has had heat removed therefrom to the atmosphere.
Type: Application
Filed: Apr 7, 2016
Publication Date: Oct 13, 2016
Applicant: Green Heat Corporation (Duluth, MN)
Inventor: Michael J. Horvath (Duluth, MN)
Application Number: 15/093,349