GB2298265A

GB2298265A - Electrically heated space heater

Info

Publication number: GB2298265A
Application number: GB9603706A
Authority: GB
Inventors: Frederick Albert Crampton
Original assignee: APOLLO HEATING TECHN Ltd
Current assignee: APOLLO HEATING TECHN Ltd
Priority date: 1995-02-23
Filing date: 1996-02-21
Publication date: 1996-08-28
Also published as: WO1996026397A1; GB9503622D0; GB9603706D0

Abstract

A space heater comprises a housing which dissipates heat generated by an electrical heater 12. Within the housing is a flow path for fluid circulated by fluid flow means (pump 19) and heated by heater 12. The housing comprises opposed walls 4 having convector fins (5, figure 2) on their inside surfaces. The flow path comprises pipe-work extending between the fins from an outlet 16 of the heater 12 between the fins to a position 23 upstream of pump 19. Fluid (preferably water) heated in the heater dissipates its heat to the walls and fins which in turn dissipate heat by radiation and convection. The heater is started automatically when flow sensed by sensor 20 exceeds a predetermined value. An internal or remote thermostat may control operation of the space heater. Vessel 30 and gauge 32 are arranged such that the pressure in the flow path can be monitored and adjusted.

Description

SPACE HEATING DEVICE This invention relates to a space heating device, particularly to such a device operated from a mains electricity supply.

Space heating devices are known which comprise a casing enclosing an electrical resistance heating element.

The casing includes inlets in a lower wall and outlets in an upper wall arranged so that cool air can enter the casing through the inlets, pass over the heating element so that its temperature is increased, after which the heated air can flow out of the outlets by convection.

Another known type of space heating device comprises a resistance heating element and a fan, the fan being arranged to drive cool air over the heating element so that the air is heated air is exhausted by the device. Use of a fan increases the heat output for a given volumetric size.

A further known type of space heating device comprises a container containing oil which is heated a by an electrical resistance heating element disposed within or against a lower part of the container.

Such known space heating devices are relatively inefficient at converting electrical energy into useful thermal energy which can be transferred into the space in which the devices are located. Furthermore, many known devices are relatively slow to reach their working temperatures.

It is an object of the present invention to address problems associated with known space heating devices.

According to the present invention, there is provided an electrically powered space heating device comprising a housing arranged to dissipate heat generated therein within to a space in which the device is located, characterised in that the housing contains means defining a flow path for a fluid within the housing. fluid flow means for causing fluid to flow in said fluid flow path, and an electrically powered heating means for heating fluid flowing in said fluid flow path.

The housing is preferably substantially made of metal and the housing is preferably arranged to dissipate heat generated therein by convection. Preferably thermal transfer from the housing by convection is assisted by means of a multiplicity of convector elements or fins forming a convection airflow path through and/or arround the device. The housing may be arranged to dissipate some heat generated within it by radiation.

The electrically powered heating means is preferably arranged adjacent a wall, such as a side wall of the housing. The heating means preferably comprises a body containing an electrical resistance heating element having an inlet for fluid to be heated and an outlet for heated fluid. The outlet is preferably located above the level of the inlet. The outlet and the inlet preferably extend in the same direction and are preferably provided on the same side of the body. Preferably the heating means comprises a heatable body and conduit means associated therewith for the flow of fluid over the heatable body. The conduit means is preferably arranged to define a convoluted fluid path around the body for the transfer of heat from the heatable body to fluid flowing in the conduit means. The conduit means forms part of the fluid flow path.Suitable heating means of this type are described in GB-B-2 265 445.

The fluid flow path preferably defines a closed flow path means formed within the housing. The majority, preferably substantially the whole, of the flow path means is arranged within the housing of the device.

The fluid flow means for causing fluid to flow in the fluid flow path preferably comprises a pump means which is electrically operated.

Fluid monitoring means is preferably arranged within the housing. Said fluid monitoring means is preferably arranged to monitor the flow of fluid in said fluid flow path. First control means is preferably provided and arranged to restrict and/or prevent operation of said heating means if the fluid monitoring means senses that no fluid is flowing in said fluid flow path or that the rate of flow is too low to prevent an exessive temperature increase in the fluid flowing through the heater.

Temperature monitoring means is preferably provided for monitoring the temperature outside said housing, for example in a space in which the device may be located.

Second control means is preferably provided for controlling the supply of power to the heating means independently of the temperature sensed by the temperature monitoring means.

The temperature monitoring means and the control means are preferably integral components of the device.

Preferably, the device is a self-contained unit. It only needs to be supplied with electrical power in order to function. The power is preferably arranged to be mains electricity although other electrical sources, such as solar charged battery supplies, may be used.

It will be seen that the space heating device according to the invention consists of a container adapted to dissipate heat generated therein primarily by convection and may represent, or be derived from, a wall mounted radiator of the type normally supplied with hot water for space heating systems. However, unlike the conventional radiator, the flow through the device is provided internally by pump means in association with an internal supply of water. Heating of the water electrically combined with water circulation through the radiator allows a high level of thermal power to be efficiently dissipated into the space in which it is located.

Specific embodiments of the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which: Figure 1 is front elevation of a space heating device (with selected parts cut away to reveal internal features of the device); Figure 2 is a cross section along line II - II of Figure 1; Figure 3 is a cross section along line III - III of Figure 1; Figure 4 is a cross section along line IV - IV of Figure 1; Figure 5 is a cross section along line V - V of Figure 1.

Referring to the Figures, a device 2 according to the the invention consists of a radiator casing including spaced apart side walls 4 which are arranged to radiate heat generated within the casing. Fixed to the inside of side walls 4 are a multiplicity of rectangular convector fins 5 which have a relatively large surface area for transfering heat to air convected through the casing.

Regions 8 and 10 of the casing 2 are not provided with convector fins 5 so that heating apparatus can be accomodated within the casing in this region.

The heating apparatus comprises a water heater 12 which is provided at one side of the casing. The heater 12 includes a water inlet 14 and water outlet 16. Upstream of the water inlet 14 is provided copper pipework 18 through which water is arranged to be pumped by an electrically powered pump 19. A flow switch 20 is associated with the pipework 18 for monitoring the flow of water in the pipework.

Downstream of the outlet 16 there is provided copper pipework 22 (not all of which is shown). The pipework 22 extends from the outlet 16 between the convector fins to communicate, at position 23, with pipework 24 which is upstream of pump 19. Thus, it will be appreciated that a closed flow path for water is defined between the inlet 14 and the outlet 16 of the heater.

A pressure vessel 30 and a pressure gauge 32 communicate with the closed flow path for water and are arranged so that the pressure in the flow path can be monitored and adjusted, if necessary.

The heating apparatus also includes a filling port 37 by means of which the flow path can be filled with water and and air outlet 38 by means of which air may be exhausted from the apparatus, in necessary. The water heater 12 is suitably of the type described in GB-B- 2 265 445.

The operation of the device 2 is as follows: the pump 19 is supplied with power so that it pumps water through the closed flow path of the heating apparatus of the device. The flow sensor 20 monitors the flow in pipework 18 and, when this is greater than a predetermined level, the supply of electricity to the water heater 12 is connected automatically. Water flowing through the heater 12 is rapidly heated and the heated water passes through the flow path arranged between the fins 5 and back to the pump 19 via the pipework 24. During its passage the relatively hot water transfers heat to fins 5 and to side walls 4 of the casing. Consequently, the side walls 4 of the casing radiate heat. Additionally, air flows into the casing and over the fins 5 by convection and the air is heated by transfer of heat from the fins as it passes over them.The relatively hot air passes out of the casing through its upper wall.

It has been found that the device 2 is very efficient at converting electrical energy into heat which can then be dissipated into the space in which the device is located.

Although reference has been made to the flow of water in the device 2, other fluids may be used. If water is used, additives may be included in the water, for example to prevent corrosion of the heater 12 and associated pipework, or the freezing of the water when the device is not in use.

The water heater 12 may be rated at, for example, 1.0, 1.5 or 2 kW. The fluid within the heating apparatus may be pressurized, for example up to 0.5 Bar (50 kP). The internal pressure will vary as the water or other fluid expands with increase in temperature. Excessive pressure is prevented by the use of expansion chambers as described previously.

The device 2 may include a built-in thermostat for controlling operation of the heating apparatus. Alternatively, a remote thermostat, placed in a suitable position in a room in which the device is arranged, may be arranged to control operation of the apparatus.

Claims

1. An electrically powered space heating device comprising a housing arranged to dissipate heat generated therein within to a space in which the device is located, characterised in that the housing contains means defining a flow path for a fluid within the housing, fluid flow means for causing fluid to flow in said fluid flow path, and an electrically powered heating means for heating fluid flowing in said fluid flow path.

2. The device as claimed in claim 1, characterised in that the housing is substantially made of metal.

3. The device as claimed in claim 2, characterised in that the housing is arranged to dissipate heat generated therein by convection.

4. The device as claimed in claim 3, characterised in that thermal transfer from the housing by convection is assisted by means of a multiplicity of convector elements or fins forming a convection airflow path through and/or arround the device.

5. The device as claimed in any of the preceding claims, characterised in that the electrically powered heating means is arranged adjacent a side wall of the housing.

6. The device as claimed in any of the preceding claims, characterised in that the electrically powered heating means comprises a seatable body and conduit means associated therewith for the flow of fluid over the heatable body.

7. The device as claimed in claim 6, characterised in that the conduit means forms part of the fluid flow path and the conduit means defines a convoluted fluid path around the body for the transfer of heat from the heatable body to fluid flowing in the conduit means.

8. The device as claimed in any of the preceding claims, characterised in that the fluid flow path is a closed flow path means and substantially the whole of the flow path means is arranged within the housing of the device.

9. The device as claimed in any of the preceding claims, characterised in that the fluid flow means for causing fluid to flow in the fluid flow path comprises electrically operated pump means.

10. The device as claimed in any of the preceding claims, characterised in that fluid monitoring means is arranged to monitor the flow of fluid in the fluid flow path.

11. The device as claimed in claim 10, characterised in that first control means restricts and/or prevents operation of the heating means if the fluid monitoring means senses that no fluid is flowing in said fluid flow path or that the rate of flow is too low to prevent an exessive temperature increase in the fluid flowing through the heater.

12. The device as claimed in any of the preceding claims, characterised in that temperature monitoring means monitors the temperature outside said housing.

13. The device as claimed in claim 12, characterised in that second control means controls the supply of power to the heating means independently of the temperature sensed by the temperature monitoring means.

14. Electrically powered space heating devices as claimed in claim 1 and as herein described.

15. Electrically powered space heating devices as herein described with reference to and as shown in the accompanying drawings.