GB2439145A

GB2439145A - Building solar and ambient heat collection to provide preheated warm air as a heat source for an air to water heat pump

Info

Publication number: GB2439145A
Application number: GB0611937A
Authority: GB
Inventors: Alan Hilton Ridett
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-06-16
Filing date: 2006-06-16
Publication date: 2007-12-19
Also published as: GB0611937D0

Abstract

The invention comprises a method by which parts of the external surface of a building can be used for the efficient collection of solar and ambient energy to supply internal space and water heating. Preferably, solar and ambient heat collection panels 1 are used as an efficient means of conducting solar and ambient heat to warm up air contained within a plenum chamber or cavity space 6 formed below or within the panels. The collection panels may be in the form of tile planks situated above a well insulated tile support system 7. Preferably, the warmed air within the plenum chamber or cavity space is used to provide an efficient preheated warm air heat source for an air to water heat pump (12, fig.3) to supply hot water and internal space heating for a building. The tile planks and insulated tile support system may be spaced apart by battens or spacers 8 to form a warm air plenum chamber or cavity space of any desired depth. The underside of the collection panels may be sprayed with an insulating foam.

Description

Page 1 Title. Efficient collection of solar and ambient heat for

buildings.

Background.

Inventors earlier patent specifications.

Original patent UK No 2,102,468 and later patents GB 222 8993 filing date 05/02/1990, grant date 22/09/1993 EP 0775283 BI filing date 31/08/1995, grant datel4/07/1999 These patents disclose systems for the importation of solar and ambient energy to efficiently heat or cool any type of building. UK No 2,102,468 & GB No 2228993 describe complete systems. EP No 0775283 Bi relates to Ambient Heat Collection Panels, now described in use as Endothermic Interlocking Tile Planks.

This new application is designed widen the use of the technology and substantially reduce fabrication and other costs. Also to make efficient use of air to water heat pumps as well as water to water heat pumps. The inventor considers this approach to be novel as an inventive step.

Statement of Invention.

A method of using Ambient Heat Collection Panels, or other conductive roofing or wall cladding materials to provide preheated warm air as a heat source for an air to water heat pump.

Advantages The system makes maximum use of solar and ambient heat as a free renewable energy source for space and water heating in buildings. It reduces the use of fossil fuels and therefore reduces carbon dioxide emissions. The system provides affordable heat.

Introduction to drawings

The invention will now be described solely by way of example with reference to the accompanying drawings in which: Figure 1 shows the extruded aluminium tile plank or Ambient Heat Collection Panel 1 similar to patent No EP 0775283.

Figure 2 shows the Ambient Heat Collection Panel 1 used as an energy harvesting roofing product passing solar and ambient heat to a plenum chamber or cavity 6 or with heated airways as a heat source for an air to water heat pump 12.

Figure 3 shows a typical house in cross section with heat collection and distribution systems.

Figure 4 shows an attic or loft housing all of the main components of the system.

page 2 Figure 5 shows a typical installation arrangement at eaves level.

Figure 6 shows a typical installation arrangement at ridge level.

Figure 7 shows the Ambient Heat Collection Panel 1 in non-liquid filled dummy form.

The warm air plenum chamber or cavity system.

This invention relates to a means of providing an abundance of preheated warm air, to act as a heat source for an air to water heat pump, the heat pump being employed to provide hot water and space heating for all types of buildings.

Alternative forms of energy are vital to sustain the quality of life that modern society has become accustomed to without causing problems associated with global warming.

Generally the efficiency of heat pumps or coefficient of performance ECOPI improves if its heat source is preheated particularly during the winter, early spring and autumn when heating demand is at its highest. This applies to water to water, air to water or air to air heat pumps.

In the example illustrated by way of drawings all of the plant and equipment has been located in the loft space which can easily be achieved in new build structures. This arrangement reduces the need for lengthy ducting and pipe work. If loft space is not available the equipment can be located in any convenient position internally or externally. The thermal store can be in buffer store form as indicated or in an insulated tank buried externally. There is a simple change over system for summer cooling in order that the feed air can be brought in from outside as the plenum chamber or cavity space would get too warm during the peak of the summer months.

Extruded Aluminium Endothermic Tile Planks or Ambient Heat Collection Panels acting as a heat source for air to water heat pumps.

Specification.

This invention can be best described as an inventive step or an alternative way to make use of the tile planks or ambient heat collection panels and systems described in the earlier patents previously referred to with their UK and EP patent numbers.

The extruded aluminium tile planks or ambient heat collection panels I which are already in use in fully flooded pumped fluid form, will remain as an interlocking dark coloured roofing or wall cladding product with the same visual appearance, with its finishing extrusions such as ridge, bay tiles and tile clip fixing arrangement also remaining in use.

The main difference between its present use and this alternative use is that the transfer of solar and ambient heat is at present achieved by using a water to water heat pump, and it is now proposed to extend the use of the roof or wall cladding product by adapting the mode of operation in order that an air to water heat pump can also be used. Although both forms of the technology will remain available, the use of an air to water heat pump will greatly reduce costs widening the market and making the energy saving technology available for most building projects resulting in increased use and massive savings in terms of carbon dioxide emissions, the major cause of global warming.

page 3 The considerable financial savings referred to are achieved by the following cost reductions.

Air to water heat pumps with both heating and cooling facilities are readily available as off the shelf appliances produced in volume by international companies. A large range with of outputs to suit most applications are available. Water to water heat pumps are not produced in similar volume and are generally purpose made costing at least twice as much to achieve comparable performance.

2 With the fully flooded pumped system a considerable amount of highly skilled welding and fabrication work is required to achieve the flow from tile plank to its adjacent tile plank up and across the roof or wall cladding. There is also a greater risk of leaks with the large number of hose connections involved. With the air to water system fabrication is kept to the minimum as welded spigots and hose connections are not required.

3 When in use with an air to water heat pump the tile planks or Ambient Heat Collection Panels I will mainly remain flooded with heat transfer fluid 2 with frost protection as required for the location. Alternatively the ducts 2 could be used as airways. In its liquid filled form sufficient air space is left in each tile plank or Ambient Heat Collection Panel 1 to allow for the expansion of the fluid on hot days. A filler! drain down nipple is fitted to the end of each plank. Although flooded to ensure efficient heat transfer from external solar or ambient heat to the plenum chamber or cavity space 6 there will be no pumped flow from plank to plank eliminating the need for welded spigots and hoses. Only five of the tile planks will remain flooded and active in atypical application with pumped flow to take advantage of direct solar radiation when available. The number of active pumped flow tile planks or Ambient Heat Collection Panels 1 could vary depending on any specific requirement. The connections from plank to plank whether in liquid or air filled form is by simple plastic plumbing pipe and off the shelf plastic tank connectors.

This heat is transferred to the store 13 via a heat exchanger 1 B fitted low down in the heat store 13. The tile planks or Ambient Heat Collection Panels I receive a baked on powder colour coat in a range of dark colours typically dark slate grey for maximum heat absorption. Having less active tile planks or Ambient Heat Collection Panels considerably lowers the fabrication costs. Increased sales of the extruded aluminium products will also reduce costs by being able to introduce assembly line production engineering techniques.

4 The air to water system will use a buffer thermal store already produced with solar input facility. This form of installation is far less costly than using a buried tank currently in use with the water to water systems. The buried in ground tank thermal store will remain an option if affordable and required for any specific application.

The heat! cooling distribution system can be by way of underfloor wet pipe system 18 or by way of individual room fan coil units 17. The use of fan coil units 17 can provide space heating in the winter and cooling in the summer and is less costly than underfloor heating.

6 All items comprising the system are robust with appropriate accreditation, but being off the shelf mass produced items are considerably lower in cost than purpose made.

7 The tile planks or Ambient Heat Collection Panels are fixed by an aluminium alloy tile plank clip 5 at each upstand or rafter position which mates with the back leg of the tile plank extrusion 5A. A stainless steel screw is used for fixing the tile clip 5. When in place the fixing clips 5 act as a track to allow the tile planks 1 to expand and move at differing roof temperatures. The tile clips 5 are a low cost extruded aluminium item, and mate with the upturn on the tile plank or Ambient Heat Collection Panels back leg 4 at position 5A.

page 4 In figure 1 the Tile Planks or Ambient Heat Collection Panels 1, internal hollow chambers 2, interlocking sections 3 and legs 4 form part of the aluminium alloy extrusion used as an energy harvesting roof or wall cladding product. Complete roof or wall cladding areas are formed by interlocking and fixing as many sections of the product as required to form an energy harvesting array. Fixing is by way of tile clip 5 mating with back leg tile plank upturn 5A. This product can be used in pumped fully flooded form using a water to water heat pump, or in a static non-pumped form using an air to water heat pump, or as an air way system using an air to water heat pump or a combination of all systems.

Figure 2 shows a typical longitudinal section through a roof creating a warm air plenum chamber or cavity 6 to provide the heat source for a air to water heat pump 12. This will greatly improve the efficiency of the heat pump 12 particularly in the late autumn winter and spring when outside ambient air temperatures are low but the plenum chamber or cavity 6 will remain warm even with the minimum of solar radiation.

The plenum chamber or cavity 6 is formed by the creation of an air space between the underside of the tile planks or Ambient Heat Collection Panels 1 and the upper sheet of the well insulated tile support system product 7 which runs from eaves to ridge in a roofing situation or as a backing member when in use as a wall cladding system. The plenum chamber or cavity illustrated is shown as 90 mm deep. This can be increased or decreased by changing the depth of the battens 8 which are either synthetic wood or plastic. In addition to the factory colour coated upper sheet of the tile support product the upper sheet is also treated with a bitumen or similar approved surface treatment to provide additional long term protection against condensation. Tile support system products 7 are available from a number of companies with a range of insulated core thickness to achieve any insulation requirement. The air intake ducts 9 fit between the structural upstands of the tile support system 7 and are all joints are sealed. The air intake ducts 9 can be made using plywood, plastic or sheet metal or can also be large diameter circular off the shelf ducting material. They are simply a means of conveying warm air from the plenum chamber or cavity 6 to the heat pump casing enclosure 11. The plenum chamber or cavity 6 covers the whole of the roof or wall cladding area which increases proportionately with the size of the building which generally has a direct relationship with the likely heating! cooling space heating load and hot water demand.

Figure 3 shows a cross section through a typical new build family home, where the loft space is retained as a warm clear space, which is partially used for the installation of an air to water heat pump 12, a thermal store 13 and all ancillary equipment such as pumps heat exchangers etc. It also shows air intake ducts 9 connecting the plenum chamber or cavity 6 to the heat air intake casing 11. The tile planks or Ambient Heat Collection Panels 1 although liquid filled there is no pumped flow. Pumped flow only occurs in tile planks 1A when there is sufficient solar gain to provide heat to the bottom of the thermal store 13 via heat exchanger I B. The tile planks 1 being powder coated a dark colour passes solar and ambient heat through to the plenum chamber or cavity 6 where the air is warmed to provide an efficient heat source for the operation of an air to water heat pump 12. The coefficient of performance of the heat pump is substantially improved by the use of the warmed air when compared to the use of air at external ambient temperatures. Figure 3 also shows a wall mounted extractor fan 19 which is activated should the loft space overheat. This is most likely to occur when the heat pump is operating in cooling mode. Also indicated are individual room fan coil units 17 and the possible use of underfloor heat distribution systems 18. The fan coil units 17 can be ceiling, wall or floor mounted.

Figure 4 shows a plan view of a typical new build clear space warm loft or attic, and indicates a possible installation arrangement with the heat pump 12 and its casing II, and the thermal storage vessel 13 and cupboard space to house all ancillary equipment. The layout may vary depending on the size and type of building. A hatch of suitable size with a staircase or loft ladder would be provided for access.

page 5 FigureS shows in section a typical arrangement at the eaves level of a new build structure and illustrates how any condensate forming on the underside of the tile planks or Ambient Heat Collection Panels 1 and perhaps dripping on occasions on to the upper protected surface of the tile support system product 7 will simply run off via the gap left in the verge trim 10 into the eaves gutter. The continuous air gap 10 which is covered by an insect screen permits adequate air intake to provide replacement air to the plenum chamber or cavity 6 required when the heat pump 12 is in operation and in heating mode.

Figure 6 shows in section a typical arrangement at the ridge level of a new build structure and indicates a method by which the air intake ducts 9 can be taken through the tile support system product 7. This could be carried out using a variety of sheet or tubular products. The depth of the plenum chamber or cavity illustrated is 90 mm but could be adjusted by changing the depth of the battens or spacers 8.

Figure 7 shows a different extrusion to tile plank 1 with the dotted sections 18 of the extrusion eliminated to save weight and cost. These could be used for complete roof or wall cladding areas or parts thereof.

page 6 Method of operation.

The temperature of the thermal store is controlled to operate over a range of 45 -55 degrees C when in heating mode. It will become hotter during the spring, summer and autumn when long periods of direct solar radiation are available.

The controller will continuously monitor the following temperatures.

a Individual room or selected space temperatures including loft space.

b External ambient air temperature.

c Plenum chamber temperatures both aspects most southerly and most northerly.

d Heat storage vessel at both low and high levels.

e Heat transfer fluid temperature at highest point of the active roof planks.

f Incoming cold water main temperature to store and F & E tank.

g Outgoing hot water temperature from top of store to domestic hot water cylinder.

h Water temperature at top of domestic hot water cylinder and feed to hot water taps.

Heating mode.

The temperature of each individual room or selected space is controlled by a wall mounted thermostat which can be set to suit individual requirements.

Whether heat distribution is by way of underfloor wet pipe system or by wall mounted Water to air fan coil units the operation is the same. As soon as the temperature in any room drops below the set temperature the heat distribution circulation pump will be activated and via a manifold will pump hot water from the top of the thermal storage vessel to the distribution system in that room until it is brought back up to the set temperature. This process could occur in a number of rooms at the same time as the individual thermostats would open the flow and return valves on the manifold ports. In say a 3 bedroom house with a first floor landing and 3 ground floor rooms and hall to heat a 8 port manifold and valving system would be installed within the storage vessel cupboard in the loft space together with the circulation pump.

As soon as the temperature of the water in the top of the storage vessel drops below 45 degrees C the controller will activate the air to water heat pump which will extract heat from the warmed air in the plenum chamber. This heat will be passed to the water circuit which will provide a flow to the storage vessel at high level with a cooled water pumped return to the heat pump at low level. As soon as the temperature at the top of the storage vessel rises to 55 degrees C the heat pump will stop running. The incoming cold water feed en-route to the domestic hot water cylinder passes through heat exchangers in the storage vessel to provide pre-heat up to 55 degrees C. At the bottom of the storage vessel an additional heat exchanger is provided which is connected via a pumped circuit to the active roof tile planks. On sunny days the dark coloured roof tile planks get very warm typically 50 -60 degrees C. As soon as the temperature probe in the active planks exceeds the temperature being monitored in the bottom of the storage vessel the circuit circulation pump is activated to provide a flow and return from the heat exchanger to the roof panels to collect this low cost heat. As soon as the roof temperature falls below the bottom of the vessel temperature the circulation pump will stop and a motorised valve will close to prevent natural thermal syphoning. During periods of extended cold dull weather should the heat pump not be able to maintain the minimum storage temperatures the back up immersion heater would cut in to provide a boost. It is also there to provide back up should any mechanical failure occur. The domestic hot water cylinder would also be fitted with an immersion heater to provide a daily temperature boost on night off-peak tariff. The daily cycle of the heat pump duty period would also be timed to commence at the start of the off peak tariff period to take advantage of the 7 hour period of low cost off-peak electricity charges.

page 7 It could run on into the normal tariff period for as long as required but for many months of the year this would not be necessary. The temperature in the loft space receiving the discharge air from the heat pump is monitored by a room thermostat which will switch on an extractor fan sized to match the airflow rate of the heat pump. This is to prevent the room and mechanical equipment overheating which is not likely in heating mode but most likely in summer cooling mode when the heated air extracted from the cooled water is discharged into the loft space and must be dumped to outside atmosphere.

Cooling mode.

The method of operation when in cooling mode during the summer months involves a simple change over procedure. The heat pump controller with remote user facility can be simply switched to reverse cycle the heat pump instructing the heat pump to extract heat from the water circuit and discharge the heat to the air side of the heat exchanger.

This heat is then discharged into the loft space and dumped to atmosphere via the extractor previously described. The only simple manual tasks required taking only a few minutes is to unbolt the three small hinged doors in the face of the winter plenum chamber ducts and to lay them down horizontally on to batten ledges and clip them down. At the front of the heat pump plywood housing there is a small door which when opened gives access to a further small door screening off the external wall air intake grille when in heating mode. This access door is clipped back to permit air flow to the heat pump from outside air during the cooling mode period. Once opened the casing door can then be shut and bolted for the duration of the cooling mode period. This procedure is then reversed to transfer back to heating mode when required.

Claims

page 8 Claims 1 A method by which parts of the external surface of any

building can be used for the efficient collection of solar and ambient energy to provide internal space and water heating.

2 In the preferred arrangement the use of the existing Ambient Heat Collection Panels I and the internal ducts 2 described in Patent No. EP 0775 283 B1 provides a means to efficiently heat the air in the cavity space or plenum chamber 6 or within the hollow sections of the extrusion for use as intake air for an air to water heat pump 12 with other conductive external finishing material also used as an architectural alternative.

3 A means of creating a plenum chamber, warm air space or cavity 6 between the underside of the Heat Collection Panels 1 and the upper surface of a insulated tile support system 7 or other similar structural liner tray system which provides a high level of insulation and an effective vapour barrier.

4 A warm air space, plenum chamber or cavity 6 as claimed in claim 2, and 3 the depth and air content of which can be adjusted by using different counter batten sizes or spacers 8.

A means of introducing fresh replacement air to the air space or cavity 6 via the verge trim 10 and the air gap at the bottom of the verge trim covered by a suitable insect screen, also permitting the discharge of any condensate that forms in the air space.

6 A method of ducting 9 to connect the air space, plenum chamber or cavity 6 to the heat pump casing 11 and heat pump 12, in any suitable sheet or tubular ducting material.

7 A preferred location for the air to water heat pump 12 is within the loft space of a new build structure where it is close to its warm air heat source 6, reducing the length of pipe runs and air ducting 9, although other locations internally or externally can be used.

8 A preferred location for the thermal store 13 is immediately adjacent to the heat pump 12 and its enclosure 11 to keep pipe runs to the minimum, although the complete assembly could be housed elsewhere as claim 7.

9 A simple transfer system to permit the intake air to the air to water heat pump 12 to be changed from winter heating mode to summer cooling mode, involving changing the air intake to the heat pump to external air via inlet 14.

A method in which the Ambient Heat Collection Panels I are not liquid filled and the voids within the extrusion 2 are used as airways to provide preheated warm air to the air to water heat pump 12 with the panels being connected using plastic pipes and fittings, and the underside of the panels being sprayed with insulating PIR foam.