JPS63210559A - Capacity controlling device and method of integrated furnace - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION BACKGROUND OF THE INVENTION The present invention relates generally to heating systems, and more particularly to space heating and tankless domestic hot water heating using infrared burner modules and heat exchange coils. Concerning modulation control for an integrated heating device for the device.

In heating systems for homes and commercial buildings, all central furnaces for heating spaces operate on the same general principle. Air for heating a space is generally circulated in a closed system containing sheet metal conduits and is heated as it passes through a heat exchanger in contact with the combustion of a fuel, or a secondary heated by the combustion of a fuel. It is heated as it passes through a heat exchanger in contact with the fluid. 500 below due to fuel combustion (
Since harmful combustion gases are produced with exhaust temperatures that can exceed 260° C., the combustion gases must be discharged to the atmosphere through a chimney or flue. Such devices are relatively inefficient due to high flue gas exhaust temperatures;
It is expensive because it requires the construction of a flue or chimney.

Indirect combustion furnaces are commonly used in both forced air and circulating pipe systems because the space to be heated is not in direct contact with the combustion gases.

A forced-flow air device mainly consists of a heat exchanger having a combustion chamber, the combustion chamber is arranged in a positional relationship such that flowing air is heated, and fuel is introduced into one end of the combustion chamber. where the combustion flame generates heat.

Heat passes through a series of internal baffles and exits through the other end of the combustion chamber into a flue or chimney. At the same time, the circulating air of the space passes outside the heat exchanger and absorbs heat by heat transfer and convection.

Circulating pipe systems mainly consist of a firebox with a heat exchanger. The heat exchanger is arranged in a closed loop device by means of which water, aqueous glycol solution or other heat exchange medium is continuously circulated from the heat exchanger to a remote radiator in the space to be heated. . However, this system is also relatively inefficient and expensive due to the temperature of the combustion gases at the exit of the firebox and the cost of the chimney.

Thus, less efficient domestic heating devices are generally the largest energy consumers, with domestic water heating devices being the second largest energy consumer. BACKGROUND OF THE INVENTION Potable water heaters or hot water tanks, usually having glass tubes, are commonly used to supply domestic hot water to homes and commercial buildings. These devices generally have an enclosed water reservoir with helical coil piping through which the heated water flows. A burner is usually arranged at the lower end of such a reservoir and the heat of the burner is allowed to pass over the coils thereby heating the water in the reservoir for use within the home or building.

Furthermore, in space heating equipment for homes and buildings,
"On time" when requesting and "off time" when waiting
Heat that is not transferred to the heat exchanger during the process is exhausted through a flue or chimney at the top of the reservoir and into the atmosphere, as well as being lost through the jacket of the reservoir. Domestic water heating systems are also inefficient because most of the heat is thus lost directly through the chimney to the atmosphere.

The increasing cost of energy has increased the need to conserve energy. As a result, there has been considerable interest in recent years in recovering energy such as waste heat from combustors that is normally exhausted to the atmosphere without being recovered.

In an attempt to regenerate waste heat, a heat exchange coil was installed in the furnace flue by which some of the waste heat was transferred to the domestic hot water heater, thus recovering some of the heat that would normally be wasted. .

However, the disadvantage of saving energy for use in domestic hot water heaters by regenerating furnace waste heat is that the two devices are independently controlled;
The energy saved is limited by the temperature of the water in the potable hot water storage tank, which is typically maintained between below 120°C (49°C) and below 160°C (71°C), with an average value equal to temperature or higher, so the regeneration efficiency is between 88% and 90%, which is the maximum limit of combustion products.
% or less. For the Blue Flame fist burner used in the re-equipment, a dual control system for the semi-integrated furnace and hot water heater is required. Dual control is required in semi-integrated equipment to provide capacity at different temperature demands for both the heating and water heating equipment - in a typical heating loop. This is because true integration is impossible. Rapid on/off response and flow control to input modulation is thus required, but blue flame burners are inherently unable to modulate effectively in this manner and therefore only require a fraction of the total input during continuous operation. operation is limited to. Since the capacity of such a burner cannot be reduced when the hot water demand is reduced, it is fired at full power capacity under all operating conditions.

Thus, there is a clear need for an integrated gas fired heating and water heating system having a modular form of capacity control system for the integrated system.

SUMMARY OF THE INVENTION The object of the invention is to provide a control device for an integrated space heating and tankless hot water heating device.

Another object of the invention is to provide a control device for an integrated heating system having a liquid-back gas-fired heating module with a radiant burner, whereby the output of the infrared burner is controlled. The required energy supply for space heating and/or domestic hot water heating is adjusted accordingly.

Yet another object of the invention is to provide a control device for an integrated heating device with a radiant burner,
The capacity of the heating device is thereby controlled more efficiently.

These and other objects of the present invention are achieved by providing volumetric modulation control for space heating in buildings and domestic hot water heating devices. A heating system with a fast-responsive liquid-back heating module and a tankless domestic water heater quickly achieves maximum radiant heat transfer capacity, thus allowing pulsing of the burner and thereby reducing the heating module's Fluid temperature is maintained within predetermined limits.

The various features of novelty which characterize the invention are pointed out by the detailed description of the claims appended to and forming a part of this specification. For a better understanding of the invention and the advantages and particular objects to be achieved by its use, reference may be made to the accompanying drawings and description in which the best mode embodiment of the invention is described and depicted. Should.

DESCRIPTION OF THE BEST PREFERRED EMBODIMENT Referring to FIG. A liquid-back heating module, Joule 12, is used to provide energy. The fluid loop further includes a fluid pump 16 and an expansion tank 28 for circulating fluid.
is included to absorb the increase in volume of fluid heated by the expansion tank and dampen pressure surges in the fluid loop. The fluid loop arrangement consists of a discharge tube 52 by which heating fluid is withdrawn from the heating module 12 as required.

The heated fluid flows through a tube-in-tube heat exchanger 50, which is a commonly used construction.

Fluid then flows through piping 54 and three-way valve 56. In the first position of three-way valve 56 , fluid is allowed to flow through line 55 directly to fluid pump 16 and back through line 57 to heating module 12 . In the second position of three-way valve 56, fluid in the loop flows through line 58 into remote fan coil 14 and through line 59 to fluid pump 1.
6 is allowed to return to the suction side.

As further shown, the domestic hot water loop includes a cold water inlet pipe 62 connected to the inlet and outlet pipes 64 of the tube-in-tube heat exchanger 50; Thereby, domestic hot water is discharged into the rear frame 43 after passing through a flow rate sensor (flow switch) 66.

A mixing valve 60 connects an outlet pipe 64 to a bypass pipe 65 . Mixing valve 60 is preferably a temperature sensitive valve,
The hot water flowing through the tube-in-tube heat exchanger 50 and the cold water flowing through the bypass pipe 65 are thereby mixed, thereby ensuring that the temperature of the hot water flowing from the tap 43 is maintained at a predetermined set point temperature. .

As further shown, the liquid-back heating module 12 includes a gas line 30 having a regulator 32 for supplying fuel to the heating module. Air is supplied to the heating module through air pipe 34. The air-fuel mixture is ignited and combusted on an infrared burner 18 centrally located within housing 20. Such air-fuel is 100% premixed, thus no secondary combustion occurs. One heat exchange device is an infrared burner 18
spaced apart from the infrared burner, thereby receiving heat from the infrared burner. The heat exchange device is generally in the form of a helical coil, through which flows a fluid that absorbs heat from the infrared burner, while transferring such heat to domestic hot water and the space to be heated. be done.

FIG. 1 shows an integrated domestic hot water/space heating system having a 1;η control system in accordance with the principles of the present invention.

The control device includes a microcomputer device 80, a system interface φ board 82, and a power supply source 83. Microcomputer device 80 includes any suitable device or device for accepting input signals, processing the received input signals according to preprogrammed procedures, and generating control signals in response to the processed input signals. It may also be a combination of devices. The control signals generated by the microcomputer device 80 are supplied to a control device, whereby the operation of the integrated heating device is controlled in response to the control signals supplied from the microcomputer device 80 to said control device.

As shown in FIG. 1, system interface board 82 is coupled to microcomputer device 80 by ribbon cable 89. The system interface board 82 includes switch devices that allow power to flow from the main power supply 83 to the three-way valve 56, fluid pump 16, induction fan 38, regulator (gas valve) 32, and igniter 40. is controlled. The switch device is preferably an electronic component, such as a relay, and is controlled in response to control signals from a microcomputer device 80, which control signals are passed through a ribbon cable 89 to electronic components on a system interface board 82. supplied to

According to the invention, the control device controls the space heating and/or
Or it is determined when the integrated heating system should be activated to meet domestic hot water requirements. For purposes of disclosing such an invention, "pulsing" means that the infrared burner is repeatedly switched on and off, and the partially induced fan is operated continuously during such pulse periods. Further, "pulse period" means the period of one pulse on and one pulse off. The infrared burner 18 of the heating module 12 has the special feature of having a rapid response time, which allows it to reach its maximum radiant heat transfer capacity quickly, i.e. within about 1 second, thus allowing the total Output energy is transferred to the fluid loop within a short period of time. More specifically, in accordance with the present invention, the temperature of the space to be heated is sensed by thermostat 85 and a signal indicative of such temperature is provided to microcomputer device 80 by wire 91. Additionally, the flow rate of domestic hot water flowing through tap 43 is sensed by flow sensor 66 and a signal indicative of such flow rate is provided to microcomputer device 80 via wire 29. Referring to FIGS. 2 and 3, the rapid response time and output capacity of the infrared burner, which allows continuous use of domestic hot water, is illustrated as a percentage of on-time.

In FIG. 2, the curve 70 passes through the stopper 43.
The one-way line 70' shows the water temperature versus time for a flow of 20 PM (7,57) 7 minutes).
Shows the water temperature versus time for a flow of minutes).

In FIG. 3, the output capacity of the infrared burner 18 is shown as a percentage of the burner on time.

Referring to FIGS. 4A to 4E, the output capacity of the burner is shown from the first time (T1) when the demand time starts and the second time (T2) when the demand time ends. Thus, FIG. 4A shows the burner at 100% capacity, or Q, with no modulation from start to finish. Elaborating on Figure 4B, a 50%
A burner of capacity i.e. 0.5Q is shown and Q' +Q
"+Q"-0.5Q. In Figure 4C, 25%
Burners in capacitance are shown, each using pulse width capacitive modulation according to the invention.

Therefore, even though the burner on pulse is modulated to vary the capacitance, the pulse duration remains constant. Furthermore, the fourth
As shown in D and 4E, the frequency of the pulse period is varied to obtain 25% capacity and 17% capacity, respectively. Thus, under the frequency modulation system,
The minimum on pulse width is maintained and the off pulse width is varied to vary the capacitance. In situations where minimum on-pulse width is required by code action, the 4th D
Frequency modulation as shown in Figures 4E may be required.

According to the invention, whenever it is necessary to pass current through the heating module, for example when flow through the tap 43 is sensed by the flow sensor 66, another control signal is sent by the microcomputer device 80 through the ribbon cable 89 to the system. Appropriate switch devices on interface board 82 are provided to provide power to ignition device 40 from power supply 83 through system interface board 82 . With such a microcomputer device, the demand for domestic hot water is determined as a function of the temperature of the closed loop fluid exiting said heating module 12, and the pulse duration of the infrared burner is adjusted so that the domestic hot water is maintained at a predetermined temperature. Ru. Furthermore, if the demand on plug 43 is reduced, the on pulse may be reduced from the pulse shape shown in FIG. 4B to the pulse shape shown in FIG. 4C.

Although the best embodiment of this invention has been illustrated and described, it will be apparent to those skilled in the art that many modifications, substitutions and changes may be made without departing from the true spirit and scope of this invention. .

For example, flow sensor 66 can be placed within piping 62 or 64.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an integrated space heating and hot water system that is an embodiment of the control system of the present invention. FIG. 2 is a graph of transient domestic hot water temperatures in response to domestic hot water demands in an integrated space heating and domestic water hot water system. FIG. 3 is a graph of percent output capacity versus percent on time during pulse periods for an integrated space heating and hot water system that is an embodiment of the control system of the present invention. Figures 4A to 4E show a comparison of full capacity control by the pulsing controller of the present invention. 10... Residential heating device, 11... Heating space, 12
...Liquid back type heating module, 14...Remote fan coil, 16...Fluid pump, 18...Infrared burner, 19...Heat exchange device, 20...Housing, 28... Expansion tank, 29... Conductor, 30...
・Gas pipe, 32... Regulator, 34... Air pipe, 36... Flue gas pipe, 38... Induction fan, 39
... Drain, 40... Ignition device, 43... Plug, 5
0...Tube-in-tube heat exchanger, 52...Discharge pipe, 54.55...Piping. 56...Three-way valve, 57.58.59...Piping, 60
...Mixing valve, 62...Cold water inlet pipe, 64...Outlet pipe, 65...Bypass pipe, 66...Flow rate sensor, 7
0.70'...Temperature rise curve, 72...Burner output capacity line, 80...Microcomputer device, 82.
...System interface board, 83...
Power supply source. 85...Thermostat, 89...Ribbon cable. 91... Electric wire patent applicant Carrier Corporation agent Patent attorney Masa Akashi
Kokyeika ■゛liev'ni・-4 (Chang 9-Cnt) F/G, 4D

Claims (2)

[Claims] (1) A burner, a coil connected in a fluid loop to a heat exchanger for transferring heat to space and for receiving heat from the burner, and having no tank and receiving heat from the fluid loop. a fluid loop comprising a domestic hot water system; a flow sensor device for sensing flow and providing a first signal to a microcomputer device directing the flow of said domestic hot water; and sensing the temperature of the fluid at the outlet of a coil receiving heat from said burner. and providing a second signal to a microcomputer device indicative of a temperature of a fluid in the fluid loop, such that the microcomputer device maintains the fluid in the fluid loop at a predetermined temperature. a temperature sensor device configured to provide an output signal for controlling a burner pulse period; and a burner flame control device. (2) sensing the flow of domestic hot water in a domestic hot water loop in a method for controlling the capacity of an integrated tankless heating device for space heating and domestic hot water heating; sensing the temperature of a fluid within the heating loop; and controlling the pulse duration of a burner that provides heat directly to the heating loop to produce a fluid at a predetermined temperature within the heating loop. A control method characterized by comprising: