JPS5825937B2 - space heating equipment - Google Patents

Description

[Detailed description of the invention] This invention relates to space heating equipment.

It consists of a closed loop of duct, which is suspended under the roof or ceiling of a building, through which air circulates as a heating fluid, and the heating effect is provided mostly by combustion radiation from the surface of the duct. It has been known to provide space heating.

For this purpose, spoilers are provided to prevent or minimize heat convection of the indoor air around the ducts, and spoilers are provided above the ducts to prevent radiant heat loss upwards of the ducts. A heat insulator is provided.

The heating effect obtained is proportional to the surface temperature of the duct, and if the air is heated through a single heat exchanger placed in the loop, then at the downstream location adjacent to the heat exchanger, the heat A much greater heating effect is obtained than in upstream locations adjacent to the exchanger.

However, if the duct is constructed in such a way that the loops have parallel parts and the heated fluid moves in opposite directions within these parts, and the height of the duct above the ground and its spacing are determined with respect to the dimensions of the area to be heated, The overlapping arrangement of the beams of radiant heat above the ground provides a substantially uniform heating effect.

Installations of the above type have considerable advantages over systems using, for example, hot water or steam as heating medium.

That is, relatively lightweight ducts can be used since the risk of leakage from the ducts is minimized, thus reducing the support required to suspend the duct system.

Any convenient fuel can be used to heat the fluid through the heat exchanger.

The object of the invention is to provide an improvement to a heating installation of the type mentioned above.

The space heating installation provided by this invention consists of a closed loop of ducts arranged above the space to be heated;
a burner arranged to discharge combustion products directly into the closed loop; and a fan operative to circulate gaseous combustion products around the closed loop to heat the space primarily with radiant heat from the loop. the loop comprises a pair of substantially parallel ducts through which gaseous combustion products flow in opposite directions;
The beams of radiant heat from the parallel ducts are arranged to overlap above the ground of the space.

The invention is thus characterized by the use of gaseous combustion products as heating medium, which gaseous products are circulated around said closed loop.

Preferably the fuel used is natural gas.

This is because natural gas can be completely combusted with little to no toxic fumes or similar combustion products.

However, other fuels such as town gas, liquefied petroleum gas and oil may also be used.

By not using a heat exchanger, the maximum temperature within the system can be substantially higher.

For example, unless constructed from expensive high-temperature materials, conventional heat exchangers operate at approximately 450'F (232°C) in a closed loop.
resulting in an airflow temperature of

According to this invention, if the combustion products from the burner are discharged directly into the closed loop, the airflow temperature is approximately 700
The temperature can be increased to below (371°C) or even higher.

Moreover, this high temperature is achieved together with high thermal efficiency and overall efficiency, and the cost of the equipment is substantially reduced.

Additionally, using a burner that releases combustion products directly into the closed loop provides a faster response to thermostatic control and lower warm-up during startup than when using a heat exchanger to heat the air in the closed loop. It takes less time.

In a preferred embodiment, combustion air is supplied to the burner together with the fuel and an outlet is provided in the closed loop;
The outlet preferably includes a control valve to limit the escape of air and combustion products from the system to a predetermined rate.

The invention will now be described by way of example and with reference to the accompanying drawings.

1-4, a first embodiment of the invention consists of a closed loop of generally rectangular duct, the closed loop of duct being placed above the space to be heated by means not shown. It is suspended from the roof of a building.

This closed loop consists of two parallel ducts N0, 11 extending in the longitudinal direction of the building and two cross headers 12,
It consists of 13.

The duct 10 comprises a gas-fired burner 14 (see FIG. 4) arranged within a rectangular section 15 of the duct, a fan 16, e.g. a centrifugal blower, arranged at the junction between the cross header 12 and the duct 10; Burner 14
This causes circulation of the gaseous combustion products released from the combustion chamber, and the combustion products go around the loop in the direction indicated by the arrows in FIG.

In FIG. 4, reference numerals 17 and 18 indicate the gas fuel and combustion air supply lines to the burner, respectively.

A fan 19 is provided to supply combustion air to the burner.

Supply line 17 is provided with appropriate control valves and safety devices to regulate the supply of fuel.

A series of motor-driven dampers 20 are provided in the duct section 15 intermediate the fan 16 and the burner 14;
Selectively open and close the circulation path around the closed loop.

The bleed duct 21 is controlled by a valve and is arranged between the fan 16 and the damper 20 and serves to exhaust a portion of the combustion products from the closed loop so that the combustion air is introduced into the closed loop by the fan 19. Compensate for.

As shown in Figures 1-3, the ducts 10, 11 and cross headers 12, 13 are connected to the tubes 2, respectively.
There are two (three in the embodiment of Figures 1-4) banks of tubes extending side by side with parallel axes in a common plane parallel to the ground of the building.

Each bank of tubes 22 has a deflection plate 23 that suppresses convection.
Each side is protected by , and the top is covered with a heat insulating plankent 24.

The deflection plate 23 and the insulation 24 thus reduce upward heat radiation and convective heat loss from the top of the tube.

The spacing between the two ducts N0, 11 is related to the height of the loop above the ground and the cross-sectional shape of the heat radiation surface of the tube 22, so that the thermal radiation beam generated by the two ducts L-10, 11 is above the ground. They are designed to overlap.

In operation, the damper 20 is initially closed and the combustion air is circulated around the closed loop, passing through the bleed duct 2.
1, thereby displacing the gas that leaked into the loop while the equipment was out of service.

The damper 20 is then opened and the gas is fed together with combustion air to the burner 14, which is ignited, for example by a spark igniter.

The mixture of air and combustion products is then circulated in a closed loop by fan 16.

The temperature of the mixture rises rapidly to the design operating temperature of the equipment;
This increases the temperature of the tube 22.

Heat is released into the interior of the building primarily by radiation, with a small degree of convection heating.

When the equipment is shut down, the fan 16 and burner 14 are shut off and the damper 20 is closed.

However, the combustion air fan 19 continues to operate for a predetermined period of time to exhaust combustion products from the closed loop.

Since one of the products of combustion is water vapor, if the combustion air fan 19 continues to operate, no condensation will occur within the tubes as they cool.

In the tests conducted, the gas input ranged from 232,000 to 4
The range is 16,000 B, t, u, /h, and the temperature in the loop is 218-434 below (103-223℃)
It became the range of .

Best overall efficiency obtained (heat output to energy manpower ratio)
was 94%, in which case 4% of the combustion gas/air mixture was bled from the loop.

In the embodiment of FIGS. 1-4, a positive pressure (relative to the atmosphere) is generated downstream of the fan 16, which pressure is sufficient to expel a portion of the combustion products from the closed loop via the bleed duct 21. It is.

However, this means that in order to pressurize the gas and combustion air into the burner 14, the pressure of the gas supplied via line 11 must be sufficiently higher than the pressure inside the closed loop and the combustion air fan 19 must be This means that the pressure must be generated sufficiently higher than the pressure inside the closed loop.

FIG. 5 shows a modification of the embodiment of FIGS. 1-4, in which fan 1
Negative pressure (relative to atmospheric pressure) is generated in the burner duct section upstream of 6.

The gas supply pressure can therefore be reduced for a given heat output, making it possible to use a small combustion air fan 19 or, in fact, eliminating the need for a fan to introduce combustion air.

In this configuration, the bleed duct is located downstream of fan 16.

Additional damper equipment may also be required to allow gas to exit the closed loop before and after burner ignition and extinguishment.

In the embodiment described above, the duct comprises a bank of three circular cross-section tubes.

However, alternative duct configurations are also possible.

For example, the tubes may be rectangular, triangular, or oblong, and instead of a bank of three tubes, each duct may consist of one, two, or more tubes.

FIG. 6 shows another embodiment of the invention, in which the closed loop consists of a relatively large duct 30 into one end of which the combustion products from a gas-fired burner 31 are discharged.

The other end of the duct 30 is connected to a cross header 32,
A cross header 32 surrounds both sides of the duct 30 and divides the combustion gases between two return ducts 33 terminating in a cross header 37 which is connected to a fan 34.
is connected to the suction side of the fan 34, and the discharge side of the fan 34 is connected to the burner 3.
1 is connected to the duct in which it is housed.

A bleed duct 35 is provided for discharging a portion of the gas from the loop, and a damper 36 is also provided as in the embodiment of FIGS. 1-4.

The loops are also suspended in the building above the space to be heated and the arrangement of the ducts 30, 33 is such that the thermal radiation beams emitted by them overlap above the ground.

Upward radiation and convection are prevented by insulation blankets (not shown) covering the tops of the ducts 30, 33 and deflection plates (not shown) along the outside of the ducts 33.

In the modified embodiment of FIG. 6, the duct 30 may consist of two or more tubes into which the burner discharge may take place.

In another embodiment of the invention suitable for heating large areas, the installation consists of a number of closed loops, as shown in FIG.

In this embodiment, the closed loops 40, 41, 42, 43 have a common cross header 44, 45 at one of their ends.

The burner 46 is arranged to discharge into the cross header 44, and the fan 48 draws the combustion gas/air mixture from the cross header 45 and circulates it past the burner and into the cross header 44, then in a closed loop. 40-43.

A bleed duct 47 is provided to draw off a portion of the circulating gas/air mixture, and a series of dampers 49 are provided in the first
It is provided for the purpose described with respect to the embodiment of FIGS.

The arrangement of the closed loops 40-43 is such that the thermal radiation beams emitted from their parallel parts overlap above the ground and also such that the thermal radiation emitted from each loop overlaps above the ground with the thermal radiation emitted from the adjacent loop. It's supposed to be rap.

Embodiment 1 Space heating installation according to the claims, characterized in that the closed loop is provided with an outlet through which part of the combustion gas circulating around the loop can be discharged.

Embodiment 2 The outlet is provided with means for regulating the rate at which combustion gases are discharged from the closed loop.

Space heating equipment according to embodiment 1. Embodiment 3 Claims, embodiment 1, further characterized in that it comprises means for supplying fuel and combustion air to the burner.
, a space heating installation according to any one of embodiments 2.

Embodiment 4 Space heating installation according to embodiment 3, characterized in that combustion air is supplied to the burner by a further fan arranged outside the closed loop.

Embodiment 5 Claims characterized in that the burner is arranged to emit its combustion products in the same direction as the flow of gas generated in the loop by the fan,
Space heating equipment according to any one of embodiments 1 to 4.

Embodiment 6 Embodiment 1 of the Claims, characterized in that the outlet of the burner is arranged inside one of the parallel ducts.
˜Space heating installation according to any one of embodiments 5.

Embodiment 7 Space heating installation according to any one of claims 1 to 6, characterized in that the fan for circulating combustion products is arranged upstream of the burner. .

Embodiment 8 According to any one of embodiments 1 to 7, the discharge port is arranged at an intermediate position between a burner and a fan that circulates combustion products. space heating equipment.

Embodiment 9 Space heating installation according to any one of claims 1 to 6, characterized in that the fan for circulating combustion products is arranged downstream of the burner. .

Embodiment 10 The space heating equipment according to any one of embodiments 1 to 8, wherein the burner is of a gas combustion type.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a building equipped with one form of space heating equipment according to the invention, with the roof omitted for clarity. FIG. 2 is an enlarged cross-sectional view taken along line 2-2 in FIG. 1. FIG. 3 is an enlarged cross-sectional view taken along line 3-3 in FIG. 1. FIG. 4 is a schematic layout of the equipment shown in FIG. FIG. 5 is a schematic layout of a modification of the embodiment of FIGS. 1-4. 6 and 7 are plan views of a building equipped with another form of space heating installation according to the invention, with the roof omitted for clarity. 10...Duct, 11...Duct, 1
2...Cross header, 13...Cross header, 14...Burner, 15...
... Rectangular section of duct, 16...
Fan, 17...Fuel supply line, 18...
... Combustion air supply line, 19 ... Fan, 20 ... Damper, 21 ... Bleed duct, 22 ... Tube, 23 ...・
... Deflection plate, 24 ... Heat insulator.

Claims (1)

[Claims] 1 comprising a closed loop consisting of a duct placed above the space to be heated, and a fan operating to circulate a heating medium within the closed loop in order to heat the space primarily with radiant heat from the closed loop; The closed loop has a pair of substantially parallel sections through which the heating medium flows in opposite directions such that the radiant heat beams overlap above the ground of the space, further forming the heating medium. a burner arranged to directly discharge combustion gas into the closed loop and having the combustion gas circulated to its intake side in the closed loop; an outlet of a duct capable of exhausting part of the combustion gas circulating in the closed loop; Space heating equipment characterized by comprising a mechanism for controlling the amount of combustion gas exhausted from the closed loop.