US20120103280A1

US20120103280A1 - Variable flow heating system with heating accessories placed in series

Info

Publication number: US20120103280A1
Application number: US13/267,207
Authority: US
Inventors: Dan Russell Wells
Original assignee: MECHANICAL SERVICE AND SYSTEMS Inc
Current assignee: MECHANICAL SERVICE AND SYSTEMS Inc
Priority date: 2010-10-08
Filing date: 2011-10-06
Publication date: 2012-05-03

Abstract

Heating systems including a boiler for heating a heating fluid, a plurality of heating accessories each requiring input of heat, piping connecting the boiler with the heating accessories, at least one of the heating accessories being placed in series relative to at least one other of the heating accessories, and a valve system including a variable speed pump and an associated control system for varying flow of the heating fluid from the boiler. Each heating accessory is configured such that heating fluid from the boiler delivered through the piping to each successive heating accessory provides heat to each heating accessory and the heating fluid is returned to the boiler at a sufficiently low temperature (e.g., no more than about 120° F.) so as to allow the returned heating fluid to be used to condense water out of flue gas generated by the boiler so as to maximize the efficiency of the boiler.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/391,118 filed Oct. 8, 2010 and entitled VARIABLE FLOW HEATING SYSTEM WITH HEATING ACCESSORIES PLACED IN SERIES, herein incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. The Field of the Invention
This invention relates to heating systems.
2. Background and Relevant Art
Modern society relies on heating systems for providing heat employed for a wide variety of uses. For example, residential and commercial properties include heating systems for providing heated water for industrial and culinary uses, heating of swimming pools, and hot tubs, as well as space heating. Relatively large properties, such as condominiums, hotels, and recreation centers often have a plurality of such accessories (e.g., culinary water, swimming pools, hot tubs, etc.), that each require heating.
Within such properties, it would be an advantage in the art to provide energy systems with increased efficiency so as to lower energy consumption and thus costs while continuing to meet the needs presented by typical accessories included within such properties.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to heating systems including a boiler comprising a heat exchanger for heating a heating fluid, a plurality of heating accessories each requiring input of heat, piping connecting the boiler with the heating accessories, at least one of the heating accessories being placed in series relative to at least one other of the heating accessories, and a valve system and associated control system for varying flow of the heating fluid from the boiler through the piping to the heating accessories. The valve system may comprise a variable speed pump. Each heating accessory may include a heat exchanger such that heating fluid from the boiler and delivered through the piping to each successive heating accessory in series provides heat to each heating accessory and the heating fluid is returned to the boiler at a sufficiently low temperature (e.g., no more than about 120° F.) so as to allow the returned heating fluid to be used to condense water out of flue gas generated by the boiler so as to maximize the efficiency of the boiler.
In one embodiment, each heating accessory may include a heat exchanger for exchanging heat from the heating fluid to another material. In another embodiment, one or more of the heating accessories may simply comprise a heating load (i.e., requiring input of heat) such as providing radiant heat to a building or other space, melting snow, etc.
Arrangement of the various heating accessories in series, as well as providing a valve system and associated variable speed pump and controls for varying the flow rate of heating fluid out of the boiler provides further efficiencies to the overall system. For example, in one embodiment, the heating accessories (e.g., each representing a load requiring input of heat, such as culinary hot water, a hot tub, a heated swimming pool, radiant heat, snow melting, etc.) are arranged in series with the heating accessory having the highest desired target temperature placed first in the series and the other heating accessories arranged in decreasing order such that the heating accessory having the lowest desired target temperature is placed last in series.
These and other benefits, advantages and features of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter

BRIEF DESCRIPTION OF THE DRAWINGS

To further clarify the above and other advantages and features of the present invention, a more particular description of the invention will be rendered by references to specific embodiments thereof, which are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

FIG. 1 is a flow chart describing the present systems and methods;

FIG. 2 is a schematic diagram of an exemplary heating system; and

FIG. 3 is a schematic diagram of another exemplary heating system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

I. Definitions

As used in this specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise.

II. Introduction

The present invention is directed to heating systems including a boiler comprising a heat exchanger for heating a heating fluid, a plurality of heating accessories each requiring input of heat, piping connecting the boiler with the heating accessories, at least one of the heating accessories being placed in series relative to at least one other of the heating accessories, and a valve system and associated variable speed pump and a control system for varying flow of the heating fluid from the boiler through the piping to the heating accessories. Each heating accessory includes a heat exchanger such that heating fluid from the boiler and delivered through the piping to each successive heating accessory in series provides heat to each heating accessory and the heating fluid is returned to the boiler at a sufficiently low temperature (e.g., no more than about 120° F.) so as to allow the returned heating fluid to be used to condense water out of flue gas generated by the boiler so as to maximize the efficiency of the boiler.
Arrangement of the various heating accessories or systems in series, as well as providing a valve system including a variable speed pump, as well as associated controls for varying the flow rate of heating fluid out of the boiler provides further efficiencies to the overall system. For example, in one embodiment, the heating accessories (e.g., each representing a load requiring input of heat, such as culinary hot water, a hot tub, a heated swimming pool, etc.) are arranged in series with the heating accessory having the highest desired target temperature placed first in the series and the other heating accessories arranged in decreasing order such that the heating accessory having the lowest desired target temperature is placed last in series.
In such an embodiment, the heating fluid (e.g., water) from the boiler is routed through the piping to the heating accessory having the highest target temperature, where the heating fluid heats water or other material to the desired target temperature within the heat exchanger of the first heating accessory. The somewhat cooler heating fluid then continues on to the second heating accessory, where the heating fluid then heats water or other material to the desired target temperature within the heat exchanger of the second heating accessory. The heating fluid thus continues on through the system, providing heat to each of the heating accessories within the heating system. After the final heating accessory, the heating fluid has been cooled to a sufficiently low temperature (e.g., no more than about 120° F.) that will allow condensation of water within the boiler flue gas. At this stage, the relatively cool heating fluid is routed back to the boiler, where it is used to condense out water vapor within the flue gas.
Condensation of the water vapor within the flue gas allows the boiler to operate at significantly higher efficiency. For example, when a boiler heats a heating fluid (e.g., by combustion of natural gas or other fuel), hot flue gas is generated. As a result of combustion of hydrocarbons, water vapor is one of the reaction products formed. Such water vapor represents a significant amount of latent heat, as it takes significant heat to convert the water into vapor form (e.g., as a result of the relatively high heat capacity and heat of vaporization of water). By way of example, a boiler may achieve about 80% efficiency, although higher efficiency is not generally possible without retrieving heat within the water vapor within the flue gas. By condensing such water vapor within the flue gas so as to recover this heat, significantly higher efficiencies can be achieved (e.g., at least about 90%, at least about 95% percent, or even higher).

III. Exemplary Heating Systems and Methods

FIG. 1 is a flow chart illustrating an exemplary method. As indicated at S10, a heating fluid (e.g., water, gycol, etc.) is heated within a boiler. As indicated at S12, the heating fluid is then delivered through a variable flow rate system from the boiler to a plurality of heating accessories placed in series relative to one another. As indicated at S14, the heating fluid is returned to the boiler at a sufficiently low temperature to allow condensation of water from the boiler flue gas.
FIG. 2 illustrates a relatively simple exemplary heating system 100 including a boiler 102. Boiler 102 includes a heat exchanger for heating a heating fluid. Piping 104 conveys the heating fluid out of boiler 102 through a variable flow rate valve and control system 106 which is configured to selectively vary the flow rate of the heating fluid out of boiler 102 and through piping 104 to the various downstream heating accessories. For example, the variable flow rate valve and control system 106 may be configured to have a turn down ratio of at least about 10:1. The turn down ratio refers to the ratio of maximum flow rate relative to the minimum flow rate that can be provided by the system without damage to the boiler. For example, a 10:1 turn down ratio refers to a system that is capable of reducing the flow rate of heating fluid at a given temperature to only one-tenth that of the maximum flow, without damage to the boiler.
Such a configuration is particularly advantageous as by reducing the flow rate of heating fluid through the system, the temperature of the heating fluid returning to the boiler will be lower than it would but for the reduction in flow rate. This results as the amount of heat capable of being transferred out of the heating fluid is a function of its temperature and volume (or flow rate). Where less heat is required by the heating accessories, either the temperature of the heating fluid may be reduced, the flow rate of heating fluid may be reduced, or a combination of both may be used. A reduction in the flow rate is particularly advantageous as it results in a lower temperature of the returning heating fluid, as the temperature of the heating fluid must drop further in order to result in the heating accessories being heated to their respective desired target temperature.
As shown, the heating system 100 includes a plurality of heating accessories 108, 110, and 112, respectively. As shown, the heating accessories are arranged in series relative to one another, such that substantially all of the heating fluid is delivered sequentially to each heating accessory. In one embodiment, heating accessory 108 may comprise a heat exchanger configured to heat culinary hot water. For example, the heating fluid from boiler 102 is delivered to the heat exchanger of heating accessory 108 and heat from the heating fluid is transferred to the culinary hot water within heating accessory 108. Exchange of heat may be accomplished by any suitable heat exchanger design (e.g., counter-current flow, co-current flow), as will be apparent to one of skill in the art.
The heating fluid is then conveyed to heating accessory 110, which may comprise, for example, a hot tub. In a similar manner, heat from the heating fluid is delivered into the hot tub so as to raise its temperature to a desired target level within a heat exchanger associated with heating accessory 110. The heating fluid is then conveyed to heating accessory 112, which may comprise, for example, a heated swimming pool. In a similar manner, heat from heating fluid is delivered into the swimming pool so as to raise its temperature to a desired target temperature within a heat exchanger associated with heating accessory 112.
Finally, after the heating fluid has been conveyed for use to each heating accessory, it is returned to boiler 102. As a result of removal of heat at each heating accessory, the heating fluid is significantly cooler when returned to boiler 102 as compared to the temperature of the heating fluid as it leaves boiler 102. At 114 cooled heating fluid is used to condense water vapor out of the flue gas generated by boiler 102. Once the heating fluid has been used to condense water vapor out of the boiler flue gas, it is then reintroduced into boiler 102, where it is reheated and cycled again through the closed loop of the heating system 100.
FIG. 3 illustrates a more detailed schematic similar to that of simplified FIG. 2. By way of example, the temperature of the heating fluid coming out of boiler 102 may be about 180° F. The target temperature of heating accessory 108 (e.g., culinary hot water) may be between about 120° F. and about 180° F. The target temperature of heating accessory 110 (e.g., a hot tub) may be between about 100° F. and about 110° F. (e.g., about 104° F.). The target temperature of heating accessory 112 (e.g., a heated swimming pool) may be between about 80° F. and about 95° F. The temperature of water returning to boiler 102 is advantageously not more than about 120° F. so that it can be used to condense water out of the boiler flue gas. The flow rate of water through the system is advantageously adjustable at valve flow controller 106 to ensure this is the case.
For example, a temperature sensor may be disposed within piping 104 (e.g., at a location downstream from the last heating accessory 112) to measure the temperature of the heating fluid at this location. If the temperature is too high then the flow rate of heating fluid through controller 106 may be decreased so as to result in a larger temperature drop of the heating fluid through the system. If the temperature is too low, the flow rate of heating fluid through controller 106 may be increased, resulting in a smaller temperature drop of the heating fluid as it cycles through the heating system.
In a preferred embodiment, the system may be capable of a variable flow rate turn down ratio of at least about 5:1, more preferably at least about 10:1. For example, a suitable variable flow rate boiler having a turn down ratio of about 15:1 is available from Aerco International, Inc., located in Northvale, N.J. Aerco's BENCHMARK series of boilers are examples of boilers having suitable characteristics.
The present invention can be embodied in other specific forms without departing from its spirit or essential characteristics. Thus, the described implementations are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims

1. A heating system, comprising:

a boiler comprising a heat exchanger for heating a heating fluid;

a plurality of heating accessories each requiring input of heat;

piping connecting the boiler with the heating accessories, at least one of the heating accessories being placed in series relative to at least one other of the heating accessories;

a valve system including a variable speed pump for varying flow of the heating fluid from the boiler through the piping to the heating accessories;

each heating accessory being configured such that heating fluid from the boiler and delivered through the piping to each successive heating accessory in series provides heat to each heating accessory and the heating fluid is returned to the boiler at a sufficiently low temperature so as to allow the returned heating fluid to be used to condense water out of flue gas generated by the boiler so as to maximize an efficiency of the boiler.

2. The heating system recited in claim 1, wherein all of the heating accessories are placed in series relative to one another.

3. The heating system recited in claim 2, wherein each heating accessory is heated to a desired target temperature by the heating fluid from the boiler.

4. The heating system recited in claim 3, wherein a heating accessory having the highest target temperature is placed first in the series of heating accessories and a heating accessory having the lowest target temperature is placed last in the series of heating accessories.

5. The heating system recited in claim 1, wherein the heating fluid is returned to the boiler at a temperature of no more than about 120° F. so as to allow the returned heating fluid to be used to condense water out of flue gas generated by the boiler so as to maximize an efficiency of the boiler.

6. The heating system recited in claim 1, wherein the heating system is a closed loop such that substantially all heating fluid leaving the boiler is returned to the boiler.

7. The heating system recited in claim 1, wherein the valve system including the variable speed pump further comprises a temperature sensor configured to measure the temperature of heating fluid returning to the boiler and wherein:

the variable speed pump increases a flow rate of heating fluid out of the boiler and through the heating accessories if the measured temperature of the returning heating fluid drops below a desired target temperature; and

the variable speed pump decreases a flow rate of heating fluid out of the boiler and through the heating accessories if the measured temperature of the returning heating fluid rises above a desired target temperature so as to maintain the temperature of the returning heating fluid within a desired target range.

8. The heating system recited in claim 7, wherein the heating fluid is returned to the boiler at a temperature of no more than about 120° F.

9. A heating system, comprising:

a boiler comprising a heat exchanger for heating a heating fluid;

a plurality of heating accessories each requiring input of heat;

each heating accessory being configured such that heating fluid from the boiler and delivered through the piping to each successive heating accessory in series provides heat to each heating accessory and the heating fluid is returned to the boiler;

a temperature sensor operatively coupled to the valve system, the temperature sensor and valve system being configured to measure the temperature of heating fluid returning to the boiler increase or decrease a flow rate of heating fluid out of the boiler to the heating accessories so as to maintain a temperature of the heating fluid returning to the boiler within a desired range so as to allow the returned heating fluid to be used to condense water out of flue gas generated by the boiler so as to maximize an efficiency of the boiler.

10. The heating system recited in claim 9, wherein all of the heating accessories are placed in series relative to one another.

11. The heating system recited in claim 10, wherein each heating accessory is heated to a desired target temperature by the heating fluid from the boiler.

12. The heating system recited in claim 11, wherein a heating accessory having the highest target temperature is placed first in the series of heating accessories and a heating accessory having the lowest target temperature is placed last in the series of heating accessories.

13. The heating system recited in claim 9, wherein the heating fluid is returned to the boiler at a temperature of no more than about 120° F. so as to allow the returned heating fluid to be used to condense water out of flue gas generated by the boiler so as to maximize an efficiency of the boiler.

14. The heating system recited in claim 9, wherein the heating system is a closed loop such that substantially all heating fluid leaving the boiler is returned to the boiler.

15. A heating system, comprising:

a boiler comprising a heat exchanger for heating a heating fluid;

a plurality of heating accessories each requiring input of heat, each heating accessory being heated to a desired target temperature by the heating fluid from the boiler;

piping connecting the boiler with the heating accessories, each of the heating accessories being placed in series relative to one another in which the heating accessory having the highest target temperature is placed first in series and the remaining heating accessories are placed in order of decreasing target temperature;

16. The heating system recited in claim 15, wherein the heating system is a closed loop such that substantially all heating fluid leaving the boiler is returned to the boiler.

17. The heating system recited in claim 15, wherein the plurality of heating accessories include culinary hot water having a highest target temperature, a hot tub having a second highest target temperature, and a swimming pool having a lowest target temperature.

18. The heating system recited in claim 15, wherein the target temperature of the culinary water is between about 120° F. and about 180° F., the target temperature of the hot tub is between about 100° F. and about 110° F., and the target temperature of the swimming pool is between about 80° F. and about 95° F.

19. The heating system recited in claim 15, wherein the heating fluid comprises heating water and each of the heating accessories comprises a heat exchanger and further comprises water requiring input of heat in order to reach the desired target temperature, the heating water from the boiler heating the water of each heating accessory to the desired target temperature within the heat exchanger of each heating accessory.

20. (canceled)