Multi-phase modular comfort controlled heating system

• US 4,337,893 A
• Filed: 11/20/1980
• Issued: 07/06/1982
• Est. Priority Date: 04/07/1980
• Status: Expired due to Term

• Current Assignee: Energy Savings Parhelion A Partnership of
• Original Assignee: Energy Savings Parhelion
• Inventors: Ness, William A., Flanders, Staunton O.
• Primary Examiner(s): Wayner, William E.
• Application Number:
  US06/208,509
• Time in Patent Office: 593 Days
• Field of Search: 236/1 EB, 236/46 R, 236/10, 236/21 B, 236/25, 126/101, 126/350 R, 237/8 R, 237/17, 237/7
• US Class Current: 237/7
• CPC Class Codes: F24D 12/02 having more than one heat source using heat pumps, in water central heating systems F24D3/18; in air central heating systems F24D5/12; in systems using heat storage masses F24D11/02
• CPC Class Codes: F24D 19/1009 for central heating
• CPC Class Codes: F24D 2200/043 More than one gas or oil fired boiler
• CPC Class Codes: F24H 15/156 Reducing the quantity of energy consumed; Increasing efficiency
• CPC Class Codes: F24H 15/176 Improving or maintaining comfort of users
• CPC Class Codes: F24H 15/212 Temperature of the water
• CPC Class Codes: F24H 15/254 Room temperature
• CPC Class Codes: F24H 15/258 Outdoor temperature
• CPC Class Codes: F24H 15/36 of burners
• CPC Class Codes: F24H 15/414 using electronic processing, e.g. computer-based
• CPC Class Codes: F24H 3/105 using fluid fuel
• CPC Class Codes: F24H 9/2085 using fluid fuel
• CPC Class Codes: G05D 23/1917 using digital means
• CPC Class Codes: Y02B 30/00 Energy efficient heating, ventilation or air conditioning [HVAC]

Abstract

A circulating fluid that is heated by a number of gas-fired burner assemblies is used to heat a space either through a hot water system or a forced air heating system. Each burner assembly includes a housing with a heat exchanger mounted therein and a gas burner for heating the fluid which flows through the heat exchanger. The heat exchangers are connected in parallel in a closed loop forced circulation system. A microprocessor based thermostat control compares the temperature in the space heated by the air with a reference temperature. Dependent upon the magnitude of the difference between the temperatures, one or more of the burner assemblies are energized. The burner assemblies are sized such that during most of the heating season only a fraction of the burner assemblies are used. Burner assemblies are cycled on and off as needed to return the temperature to the steady state during the warmer and colder parts of the heating season at least one burner assembly is usually in operation during a majority of the heating season.

Claims

1. A gas-fired space heating system, comprising:

(a) a plurality of modular incremental gas-fired burner assemblies each including

a housing,

heat exchanger means mounted in the housing for effecting heating of a fluid in contact therewith, said heat exchanger means comprised of a thermally conductive material with a heat transfer surface area that is large enough relative to the volume of said fluid in contact therewith and the flow rate of said fluid so that thermal energy is transferred to said fluid substantially instantaneously when said heat exchanger means is heated, and

a gas burner mounted in the housing for effecting heating of the thermally conductive material of said heat exchanger means;

(b) a low mass closed loop circulation system for transferring heat from said fluid to a space to be heated, said circulation system including moving means for continuously moving said fluid into contact with said heat exchanger means to effect heating of said fluid when any one of said gas burners is in operation, said moving means circulating substantially all of the fluid confined within said circulation system through said plurality of heat exchangers, whereby the heat added to said fluid by the firing of one additional gas burner is manifested by a direct increase in temperature in the space being heated without a delay due to the time needed to heat a mass of ambient temperature fluid and heat is continuously removed from said system at a rate that is substantially the same as the rate at which heat is added by said gas burners;

means for measuring the air temperature in said space;

firing means for individually firing the gas burner in each of said burner assemblies to effect heating of the associated heat exchanger means and incremental heat transfer to said fluid; and

means for comparing the air temperature in a space to be heated with a reference temperature and for activating said firing means to fire one or more of said burners as a function of the difference between said measured space temperature and said reference temperature.

2. The heating system of claim 1, in which the fluid in contact with said heat exchanger means is water and said heat exchanger means are disposed in a reverse parallel flow relationship with said moving means.

3. The heating system of claim 1, in which the fluid in contact with said heat exchanger means is air.

4. A gas-fired system for heating an enclosed space, comprising:

a heating chamber;

a blower for driving air through the heating chamber to said space;

first heat exchanger means disposed in said heating chamber for transferring heat from heated water contained therein to the air in said chamber, said first heat exchanger having an outlet and an inlet;

a plurality of gas-fired burner assemblies each including;

a housing having a vent opening for exhausting combustion gases to the atmosphere;

a burner heat exchanger mounted in the housing for carrying the water for heating; and

a gas burner mounted in the housing for heating the water in the burner heat exchanger;

a water pump for circulating the water in a closed loop between said first heat exchanger means and said plurality of burner heat exchanger means, the outlet of the first heat exchanger means being coupled to its inlet by said closed circulation loop including said plurality of burner heat exchanger means and said water pump;

means for measuring the temperature of the air in the space into which air from the heating chamber is exhausted;

firing means for individually firing the gas burner in each burner assembly to effect heating of the associated burner heat exchanger and water circulating therethrough to effect incremental increase in the heat transferred to the water circulated through said first heat exchanger means; and

means for comparing said measured air temperature with a reference temperature and for activating the firing means to fire one or more of said burners as a function of the incremental heat required to maintain the temperature in said space at said reference temperature.

5. The system set forth in claim 4, wherein said burner heat exchangers are joined together in a reverse parallel relationship with each other and a series relationship with said first heat exchanger.

6. The heating system of claim 4, in which the result of said comparison is the difference between said measured temperature and said reference temperature, said comparison means selectively activating said firing means to sequentially and incrementally fire the burners as a function of said comparison result.

7. The heating system of claim 6, in which said comparison means includes means for selecting a plurality of temperature difference ranges corresponding to said comparison result and for sequentially activating the firing means to fire or extinguish successive burners as the comparison result shifts from one temperature difference range to another.

8. A gas-fired, multi-phase heating system for a space, comprising:

a heating chamber;

means for forcing air through the chamber and to said space;

a first heat exchanger for transferring heat from a heated fluid to the air in said chamber, said first heat exchanger being mounted in the chamber and having an outlet and an inlet;

a plurality of gas-fired burner assemblies each including;

a housing defining an upper chamber having a vent opening for exhausting combustion gases and defining a lower chamber,

a burner heat exchanger mounted in the housing intermediate the upper and the lower chamber for transferring heat to the fluid contained therein, and

a gas burner for heating a fluid in the burner heat exchanger mounted in the lower chamber of the housing, which lower chamber in a typical crosssection tapers from the general vicinity of the gas burner to the location of the burner heat exchanger, whereby heated combustion gases from the gas burner are focused on the burner heat exchanger;

circulating means for circulating the fluid in the first heat exchanger through the burner heat exchangers and back to the first heat exchanger, the outlet of the first heat exchanger being coupled to its inlet by the burner heat exchangers and said circulating means;

means for measuring the temperature of the air in the space into which air from the heating chamber is exhausted;

firing means for individually firing the gas burner of each said burner assembly to effect heat transfer to the fluid circulating through the burner heat exchanger associated therewith to thereby change the heat transferred to said first heat exchanger in discrete increments; and

means for comparing said measured air temperature with a reference temperature and for activating the firing means to fire different numbers of said gas burners in accordance with the magnitude of the difference between said temperatures.

9. The heating system of claim 8, in which the burner heat exchangers are connected in parallel between the outlet of the first heat exchanger and its inlet, and in which the fluid which is circulated is water.

10. The arrangement of claim 9, in which the comparison means activates the firing means to fire said burners sequentially and cumulatively.

11. A heating arrangement, comprising:

a heating chamber;

means for forcing a first fluid from the heating chamber to a second chamber;

a first heat exchanger for carrying a heated second fluid, said first heat exchanger being mounted in the heating chamber and having an outlet and an inlet;

a plurality of burner assemblies each including;

a housing,

a burner heat exchanger mounted in the housing for carrying said second fluid and for transferring heat to said second fluid, and

a burner mounted in the housing for heating that portion of said second fluid in the burner heat exchanger;

means for circulating said second fluid from the first heat exchanger through all the burner heat exchangers and back to the first heat exchanger, the outlet of the first heat exchanger being coupled to its inlet by the burner heat exchangers and said circulating means;

means for measuring the temperature in said second chamber;

firing means for individually firing the burner of each said burner assembly;

means for comparing said second chamber temperature with a selected reference temperature and for activating said firing means to fire one or more of said burners according to the difference between said temperatures to effect an incremental increase in the temperature of said second fluid circulating through said first heat exchanger in response to the firing of each burner;

a clock;

means for storing a plurality of reference temperatures and an associated time and for selecting a reference temperature from the plurality of reference temperatures dependent upon the time associated with the clock.

12. A method for heating an enclosure to maintain the temperature of the enclosure generally uniform by burning fuel while optimizing the utilization of the fuel, comprising the steps of:

(a) locating a plurality of spaced apart modular burner assemblies in a parallel array so as to define a first assembly and an oppositely disposed last assembly, each of said burner assemblies including

a walled housing,

heat exchanger means for transferring heat to a first fluid, and

burner means mounted in said housing for heating said heat exchanger means, whereby the heat produced by said burner means is used to increase the temperture of the first fluid;

(b) circulating substantially all of said first fluid in parallel through all said burner heat exchangers and then circulating the fluid flowing out of said burner heat exchangers through said enclosure in a generally closed loop, said fluid entering said burner heat exchangers at one end of said array adjacent said first assembly and leaving at the opposite end of the array adjacent said last assembly;

(c) transferring at least a portion of the heat added to the circulating first fluid from said incrementally fired burner assemblies to the interior of said enclosure, whereby heat is transferred to said fluid by a forced circulation system disposed in a reverse parallel flow relationship;

(d) sizing the burner assemblies such that the steady state thermal energy produced by all of said burner assemblies when transferred to the interior of said enclosure by the forced circulation of said first fluid being generally equal to that heat transferred from the interior of said enclosure to the exterior of said enclosure for a selected first temperature difference between the interior and the exterior of said enclosure, the steady state thermal energy produced by one of said burner assemblies when transferred to the interior of said enclosure through the forced circulation of said first fluid being generally equal to the heat transferred from the interior of said enclosure to the exterior of said enclosure for a selected second temperature difference between the interior of said enclosure and the exterior of said enclosure, said second temperature difference being a fractional part of said first temperature difference, whereby the temperature in said enclosure is maintained relatively constant by firing at least one and less than all of said burner assemblies when said temperature difference has a value generally less than said first temperature difference and greater than or equal to said second temperature difference;

(e) measuring the temperature at the interior of said enclosure;

(f) comparing the temperature at the interior of said enclosure with a selected reference temperature;

(g) activating one or more of said burner assemblies according to the difference between said reference temperature and the temperature at the interior of said enclosure, said last burner assembly being activated when the difference in temperature between said reference temperature and the exterior of said enclosure is generally greater than said second temperature difference, whereby heat is transferred to the interior of said enclosure almost instantaneously;

(h) operating at least one burner assembly at its highest combusion efficiency during a substantial portion of the heating operation to minimize start-up losses, and standby losses;

(i) activating additional burner assemblies one at a time in response to the difference between said reference temperature and the temperature at the interior of said enclosure when the heat lost from said enclosure exceeds the amount of heat transferred to the interior by the forced circulation of said first fluid, all of said burner assemblies being activated when the difference between said reference temperature and the exterior of said enclosure is generally greater than said first temperature difference, whereby the interior temperature of said enclosure is maintained relatively constant by changing the heat transferred to the interior of said enclosure in discrete increments, each increment being generally a fraction of the total energy transferred to said enclosure when all of the assemblies burner are operated; and

(j) sequentially deactivating said burner assemblies one at a time when the heat added to said enclosure exceeds the heat lost to the exterior of the enclosure.

13. A heating system for an enclosure, comprising:

(a) an array of spaced apart modular burner assemblies each including

a walled housing,

a burner heat exchanger carried by said housing for ducting a first fluid through said housing and for transferring the heat therein to said first fluid, and

burner means, mounted in said housing, for heating the interior of said housing, whereby the heat produced by said burner means is used to heat said first fluid flowing through said housing;

(b) forced circulation heating means for circulating substantially all of the mass of that portion of said first fluid to be heated in parallel through said burner heat exchangers and all of the fluid flowing out of said burner heat exchangers through said enclosure, said forced circulation means defining a plurality of conduit elements the volume of which is on the order of the volume of said burner heat exchangers, whereby the time rate of temperature change at the interior of said enclosure due to the firing of one additional burner means is proportional to the time rate of flow of said first fluid, startup losses are minimized, and each gas burner is operated at its highest combustion efficiency soon after being placed in operation;

(c) measuring means for measuring the temperature at the interior of said enclosure;

(d) firing means for individually firing the burner means in each of said burner assemblies;

(e) comparison means, operatively associated with said measuring means and said firing means, for comparing the temperature at the interior of said enclosure with a selected reference temperature and for activating and de-activating one or more of said firing means sequentially and cumulatively according to the difference between said reference temperature and the temperature at the interior of said enclosure to increase the heat transferred to the interior of said enclosure in discrete increments and maintain the interior temperature of said enclosure relatively constant with at least one of said burner means being operated at its highest combustion efficiency, each subsequent firing means being activated by said comparison means when the heat lost from said enclosure exceeds the amount of heat transferred to its interior by said forced circulation means by said burner means then activated, the relative volume of fluid occupying the non-activated burner assemblies decreasing in discrete fractional amounts as the relative temperature difference between the circulating fluid in the non-activated burner assemblies and the interior of the associated walled housing increases as additional burner assemblies are placed in service, whereby the relative amount of standby losses does not substantially increase,

the activated burner assemblies being sequentially de-activated when the heat added to said enclosure exceeds the heat lost.

14. The heating system set forth in claim 13, wherein the steady state thermal energy produced by all of said burner assemblies when transferred to the interior of said enclosure through said forced circulation means is generally equal to the heat loss from the interior of said enclosure for a selected first temperature difference between the interior and the exterior of said enclosure, the steady state thermal energy produced by one of said burner assemblies when transferred to the interior of said enclosure through said forced circulation means is generally equal to the heat loss from the interior of said enclosure for a selected second temperature difference between the interior and the exterior of said enclosure, said second temperature difference being a fraction of said first temperature difference, whereby the temperature in said enclosure is maintained relatively constant by firing at least one and less than all of said burner assemblies when said temperature difference has a value generally less than said first temperature difference and greater than or equal to said second temperature difference,

said steady state condition of said furnace system occuring when startup losses and standby losses are minimized and combustion efficiency is maximized.

15. A heating system for an enclosure, comprising:

(a) an array of spaced apart modular burner assemblies each including

a walled housing,

a burner heat exchanger carried by said housing for ducting a first fluid through said housing and for transferring the heat therein to said first fluid, and

burner means, mounted in said housing, for heating the interior of said housing, whereby the heat produced by said burner means is used to heat said first fluid flowing through said housing;

(b) forced circulation heating means for circulating substantially all of the mass of that portion of said first fluid to be heated in parallel to contact said burner heat exhangers and for circulating all of the fluid flowing from said burner heat exchangers to effect heating of said enclosure, whereby the time rate of temperature change at the interior of said enclosure due to the firing of one additional burner means is proportional to the time rate of flow of said first fluid, startup losses are minimized, and each gas burner is operated at its highest combustion efficiency soon after being placed in operation;

(c) measuring means for measuring the temperature at the interior of said enclosure;

(d) firing means for individually firing the burner means in each of said burner assemblies;

(e) comparison means, operatively associated with said measuring means and said firing means, for comparing the temperature at the interior of said enclosure with a selected reference temperature and for activating and de-activating one or more of said firing means sequentially and cumulatively according to the difference between said reference temperature and the temperature at the interior of said enclosure to increase the heat transferred to the interior of said enclosure in discrete increments and maintain the interior temperature of said enclosure relatively constant with those of said burner means having been fired being operated at their highest combustion efficiency, each subsequent firing means being activated by said comparison means when the heat lost from said enclosure exceeds the amount of heat transferred to its interior in response to the burner means then activated, the relative volume of fluid in contact with the non-activated burner assemblies decreasing in discrete fractional amounts as the relative temperature difference between the circulating fluid in contact with the non-activated burner assemblies and the interior of the associated walled housing increases as additional burner assemblies are placed in service, whereby the relative amount of standby losses does not substantially increase,

the activated burner assemblies being sequentially de-activated when the heat added to said enclosure exceeds the heat lost.

16. The heating system set forth in claim 15, wherein:

said burner heat exchanger includes at least one of the walls of said housing;

said first fluid is air; and

said forced circulation heating means includes a blower which circulates air around the exterior of said housing and through duct work disposed in a series flow relationship with the interior of said enclosure,

whereby heat from said burner means is transferred to the interior of said enclosure when said burner means and said blower are activated.

17. The heating system set forth in claim 15, wherein

each of said burner heat exchangers has an inlet and an outlet connection, said inlet connections being joined to a common inlet header and said outlet connections being joined to a common outlet header;

said first fluid is water;

said forced circulation heating means includes a pump for inducing flow from said inlet header to said outlet header, an enclosed chamber, a blower disposed in a series flow relationship with said enclosure and said enclosed chamber, and heat exchanger means disposed in a series flow relationship with said pump, for ducting said water through said chamber and for transferring heat from water to the air in said chamber, said pump circulating fluid from said outlet header through said heat exchanger means and to said inlet header in a closed loop,

whereby when said pump is running, said blower is in operation and one of said burner means is fired, heat is transferred to said enclosure.

18. The heating system set forth in claim 15, wherein said burner heat exchanger includes at least one horizontal finned tube;

said burner means is disposed below and parallel to said finned tube; and

said housing includes at least one wall disposed convergingly between said burner means and said finned tube, whereby heat from said burner means flows upwardly along said one wall and transversely across the said tube.

19. The heating system set forth in claim 15, wherein:

said housing defines a lower chamber and a spaced apart upper chamber;

said burner means is a gas burner disposed in said lower chamber, each of said upper chambers are joined to a common outlet plenum for discharging the combustion gases from said gas burner;

said burner heat exchanger includes at least one tube joining said lower chamber with said upper chamber; and

said first fluid is air;

further including a mixing chamber for enclosing said burner heat exchanger tubes, said mixing chamber having an inlet connection and an outlet connection; and

wherein said forced circulation means includes a blower for circulating air from said inlet connection across said tubes and to said outlet connection, whereby the air heated by said gas burners is funneled together in heating said enclosure.

20. The heating system set forth in claim 15, wherein said burner means includes a gas burner and all of the gas burners within said burner assemblies are connected to a common gas supply manifold;

and said firing means includes a solenoid valve disposed in a series flow relationship between said gas supply manifold and the associated gas burner.

21. The heating system set forth in claim 15, wherein said housing includes an outlet chamber and a spaced apart firing chamber carrying said burner means and said burner heat exchanger includes a duct disposed between and joining together said firing chamber and said outlet chamber;

and

further including a common mixing chamber surrounding said ducts, whereby air within said mixing chamber is heated by the hot combustion gases and air flowing through said ducts when at least one burner means is fired.

22. The heating system set forth in claim 15, wherein said first fluid is air and said forced circulation means includes blower disposed in series flow relationship with the interior of said enclosure, whereby air heated by said burner means is transferred to the interior of said enclosure when said blower is running.

23. The heating system set forth in claim 15, wherein said burner heat exchanger is formed from a heat conductive metal, and wherein the surface area of said burner heat exchanger heated by said burner means is sufficiently large such that the rate of heat transfer across said burner heat exchangers is proportional to the temperature difference between the interior and exterior of said burner heat exchanger.

24. The heating system set forth in claim 15, in which said comparison means includes:

(a) means for selecting a plurality of temperature difference ranges corresponding to said comparison result and;

(b) means for sequentially activating each of said firing means to activate or de-activate one or more of said burner means as the comparison result shifts from one temperature difference range to another.

25. The heating system set forth in claim 15, wherein said burner heat exchangers are disposed in a parallel flow arrangement so that said first fluid when circulated by said forced circulation heating means flows across each of said burner heat exchangers.

26. The heating system set forth in claim 15, wherein said comparison means includes:

(a) a clock timer;

(b) means for storing a plurality of reference temperatures each having an associated time; and

(c) means for selecting a reference temperature from said plurality of reference temperatures depending upon the time associated with said clock timer, whereby the temperature in said enclosure is compared with a reference temperature depending upon the time on said clock timer in activating and deactivating said firing means.

27. The heating arrangement set forth in claim 15, wherein each burner heat exchanger includes a horizontal finned tube, and wherein the walls of said housing are substantially disposed against the edges of said fins, whereby said housing focuses the heat from said burner means towards said finned tube.

28. The heating system set forth in claim 23, wherein the sum of the products of the effective heat transfer area of each burner heat exchanger and the temperature difference between the interior and the exterior of that burner heat exchanger is generally equal to the product of the number of heat exchangers with the effective heat transfer area of any heat exchanger and the temperature difference between the interior of the heat exchanger and the exterior of that heat exchanger.

29. The heating system set forth in claim 15, wherein the interior volume of each walled housing is joined to a common flue which is vented to the atmosphere, whereby the heat transferred to the atmosphere by the convection of air flowing through the deenergized burner assemblies when at least one of said burner assemblies is energized is less than that heat transferred to the atmosphere from a burner assembly having an interior volume generally equal to the total interior volume of said burner assemblies and a burner heat exchanger with an effective surface area generally equal to the total effective surface area of said burner assemblies.

30. The heating system set forth in claim 15 further including:

means for measuring the temperature at the exterior of said enclosure; and

means for comparing the exterior temperature with the temperature at the interior of said enclosure and for activating said firing means sequentially and cumulatively according to the difference between the interior and exterior temperatures, one of said firing means being activated when the temperature difference is greater than said second temperature difference and all of said firing means being activated when the temperature difference is greater than said first temperature difference,

whereby burner means are activated and de-activated sequentially while maintaining the interior temperature relatively constant and while minimizing the temperature variation in said enclosure due to a variation in the exterior temperature.

31. The heating system set forth in claim 15, wherein the steady state thermal energy produced by all of said burner assemblies when transferred to the interior of said enclosure is generally equal to the heat loss from the interior of said enclosure for a selected first temperature difference between the interior and the exterior of said enclosure, and wherein the steady state thermal energy produced by one of said burner assemblies when transferred to the interior of said enclosure is generally equal to the heat loss from the interior of said enclosure for a selected second temperature difference between the interior and the exterior of said enclosure, said second temperature difference being a fraction of said first temperature difference, whereby the temperature in said enclosure is maintained relatively constant by firing at least one and less than all of said burner assemblies when said temperature difference has a value generally less than said first temperature difference and greater than or equal to said second temperature difference,

said steady state condition of said furnace system occuring when startup losses and standby losses are minimized and combustion efficiency is maximized.