Patent Description:
Heat pumps are commonly used for providing heating or cooling to buildings, i.e. HVAC applications, due to their relatively low running costs and friendliness to the environment. Development has for several years been trending towards many households and business buildings switching from aging more expensive HVAC systems to a heat pump based system, such that the heat pump alone provides the heating or complements the older system.

Heat pumps use refrigeration cycles in which a refrigerant is used for collecting and delivering heat. The heat pumps may be reversible, i.e. the condenser and the evaporator may switch functionality.

Air source heat pumps generally comprise an outdoor unit. A known problem with this unit is that it generates a lot of condensate, and as development leads to more efficient heat pumps, even more condensate is produced. Many heat pumps lack a built in solution for taking care of the condensate, and therefore rely on external trays which are fitted below the heat pump. These are however sensitive to freezing of the condensate and to debris such as leaves clogging the outlet of the tray.

Document <CIT> discloses a mounting and collection pan for an air conditioning unit comprising the features of the preamble of claim <NUM>.

It is an object of the teachings herein to provide a drainage tray for a heat pump which is improved over prior art, alleviating known problems thereof. This object is achieved by a concept having the features set forth in the appended independent claim; preferred embodiments thereof being defined in the related dependent claims.

According to a first aspect of the teachings herein, a drainage tray for collecting condensate from a heat pump is provided. The heat pump is adapted to be mounted on a support, said support being mountable to at least one supporting structure (such as the ground and/or an external building wall) to carry the weight of the heat pump and the support. The tray comprises a peripheral and preferably inclined edge portion defining a central recessed tray portion configured to collect condensate, and the tray further comprises a condensate outlet for removing the condensate from the tray. The tray is configured to be arranged between an underside of the heat pump and the support. Since the distance between the tray and the heat pump is minimized, the risk of freezing condensate, spilling of condensate and debris falling into the tray is reduced, and a tray which is improved over prior art is thereby provided.

According to one embodiment the drainage tray further comprises at least two lateral recessed portions on the opposite side of the tray in relation to the central recessed portion. The lateral recessed portions essentially correspond to supporting members on the support such that the tray is supported by the contact between the at least two lateral recessed portions and the support. The lateral recessed portions are shaped and positioned for securing the tray and preventing sideways motions in the longitudinal direction of the tray.

According to one embodiment, the at least two lateral recessed portions further comprise a rubber coating covering at least a part of the at least two lateral recessed portions for increasing friction between the tray and the support. The rubber coating provides dampening of any noise that might be caused by vibrations or by wind and increases the friction between the tray and the support.

According to one embodiment of the teachings herein, a first of the lateral recessed portions is adapted for restricting motion of the tray in two directions and a second of the lateral recessed portions is adapted for restricting motion of the tray in one direction. The different shape of the first and second recessed portions will facilitate insertion and removal of the tray and also provide larger dimensional span of the supports which support the tray will fit onto.

According to the invention, the drainage tray has an essentially trapezoidal shape in a horizontal plane, i.e. a plane parallel to the underside of the heat pump. The shape of the tray corresponds to the L-shaped condenser of many heat pumps. It is possible to adapt the tray according to shape of the condenser since the vicinity of the tray to the heat pump reduces the effect of wind or other external forces on the drops of condensate.

According to one embodiment, the drainage tray comprises a top tray portion and a bottom tray portion. The top and bottom portions are connected along a peripheral edge of the tray, and a hollow centre portion is formed within the tray between the top and bottom portions. The hollow centre portion provides an insulating air layer between the central recessed portion and the bottom portion which is in contact with the support.

In one embodiment an electrically heated sheet is arranged within the hollow portion, said sheet being attached to the underside of the top tray portion such that it evenly heats the central recessed portion of the tray avoiding freezing of the condensate. The heated sheet keeps the condensate from freezing and heats the central recessed portion and even at least a part of the inclined edge portion.

According to one embodiment, an insulating sheet is arranged within the hollow portion, said sheet being attached to the top side of the bottom tray portion. The insulating sheet increases the efficiency of the tray in combination with the electrically heated sheet.

In one embodiment of the teachings herein, the insulating sheet is spaced from the heating sheet within the hollow portion such that further insulation is provided by intermediate air between the insulating sheet and the electrically heated sheet.

According to one embodiment, the drainage tray is made from a polymer material, preferably ABS/PMMA.

In one embodiment of the teachings herein, a hose is connectable to the outlet of the tray, said hose being insulated and configured to be heated by an internal heating element.

In one embodiment, the recessed portion for collecting condensate is configured to hold a volume of at least <NUM>,<NUM> condensate, and more preferably at least <NUM>,<NUM> condensate. The volume of the central recessed portion provides a buffer volume which is beneficial if for instance if a blockage occurs in the outlet of the tray or in the hose.

In one embodiment, the drainage tray has a height of between <NUM> and <NUM>, preferably <NUM>.

In a second aspect of the teaching herein, a heat pump system is provided. The system comprising a heat pump, a support and a drainage tray according to the first aspect, wherein the heat pump is arranged on the support via bushings having a height of between <NUM> and <NUM>, more preferably between <NUM> and <NUM> and even more preferably <NUM>, said bushings creating a space between the underside of the heat pump and the support configured for receiving the tray.

Embodiments of the teachings herein will be described in further detail in the following with reference to the accompanying drawings which illustrate non-limiting examples on how the embodiments can be reduced into practice and in which:.

With reference to <FIG>, a heat pump system <NUM> is shown. The heat pump <NUM> is positioned on a support <NUM>. The support is mounted to or resting on a supporting structure, in <FIG> this is the ground and an optional wall behind the support for further stability. The supporting structure is defined as the structure or structures which bear the load from the heat pump and the support. The support <NUM> could also be a wall mounted support, where the only supporting structure is a wall. The support <NUM> comprises a plurality of supporting members <NUM>, onto which the heat pump <NUM> is mounted. The support <NUM> is preferably made out of metal, such as galvanized steel, stainless steel, aluminium or another metal with high corrosion resistance. Other materials are also possible, such as plastics or composite materials.

The heat pump <NUM> shown is an outdoor unit which is adapted to be connected to an indoor unit for providing heat or cooling and regulating the indoor climate.

The heat pump <NUM> may be mounted onto the support <NUM> via bushings <NUM> attached either directly to the underside of the heat pump <NUM> or to heat pump mounting feet <NUM> which are attached to the heat pump <NUM>. The bushings <NUM> are made of a resilient material, such as rubber, and intended to absorb and reduce the risk of any possible vibrations in the heat pump <NUM> being transferred to the support <NUM> and onwards to the supporting structure. The bushings <NUM> have a height of between <NUM> and <NUM>, more preferably between <NUM> and <NUM> and even more preferably <NUM>. Thus a space is provided between the underside of the pump <NUM> or the mounting feet <NUM> of the pump and the support <NUM> which essentially corresponds to the height of the bushings <NUM>.

The space between the pump <NUM> and the support <NUM> is adapted for receiving a drainage tray <NUM> according to the teachings herein. The drainage tray <NUM> is adapted to receive the condensate which is being produced by the pump <NUM> and which drips from drainage holes in the underside of the pump <NUM>. By providing the space between the pump <NUM> and the support <NUM> and a drainage tray <NUM> adapted for being arranged in said space, the tray <NUM> can be brought closer to the underside of the pump <NUM>. This is an advantage since it will reduce the falling distance for condensate drops from the pump <NUM>, which reduces the risk of drops being affected by wind such that they fall to the side of the tray. The risk of condensate freezing during cold temperatures also decreases.

A small distance between the tray <NUM> and the underside of the pump <NUM> is also an advantage since it reduces the risk of debris such as leaves landing in the tray <NUM>.

The tray further comprises a hose <NUM> for removing the condensate from the tray <NUM>. The hose may comprise insulation and may furthermore be configured to be heated by a heating element, such as a heating cable, to ensure that the condensate does not freeze in the hose.

Turning to <FIG>, a perspective view is shown of a drainage tray <NUM> according to the teachings herein. The tray <NUM> has an essentially trapezoidal, oblong shape in a horizontal plane i.e. in a plane parallel to the underside of the heat pump. Many of the leading manufacturers of heat pumps use L-shaped condensers, when seen from above, which are positioned in the heat pumps <NUM> in similar manners. The shape of the tray <NUM> can thereby be optimized, as the drops will fall from the condenser through the holes in the underside of the pump <NUM> in an essentially L-shaped pattern. This is made possible by the tray <NUM> being brought closer to the pump <NUM>, ensuring that the drops of condensate will fall straight down into the tray <NUM>. An advantage with the optimized shape is the reduced manufacturing cost due to less material being required for the tray.

The tray <NUM> further comprises an outlet <NUM>, through which the collected condensate drains. The hose <NUM> is connectable to the outlet <NUM> for instance by means of a threaded connection or a quick lock connection. The tray <NUM> also comprises a peripheral inclined edge portion <NUM> forming a central recessed tray portion <NUM>. The inclined edge portion <NUM> prevents the condensate from spilling off the side of the tray, and the central recessed tray portion <NUM> which faces the underside of the pump <NUM> can hold a certain volume of condensate. This is beneficial since if a blockage occurs in the outlet <NUM> or in the hose <NUM>, the recessed tray portion <NUM> will function as a buffering volume, providing a longer time span until condensate overflows the inclined edge portion <NUM>. The volume of the central recessed portion <NUM> is at least <NUM>,<NUM> in the disclosed embodiment, more preferably more than <NUM>,<NUM><NUM>. The volume is preferably in the range of <NUM> - <NUM>,<NUM><NUM>. The inclined edge portion <NUM> has an incline of approximately <NUM>° to <NUM>° in the disclosed embodiment or more preferably approximately <NUM>° in relation the surface in the central recessed portion <NUM>.

In <FIG>, the tray <NUM> is shown as seen from above with an outline <NUM> of a how the L-shaped condenser in a heat pump is oriented in relation to the tray <NUM>. The shape of the tray <NUM> is optimized in relation to the condenser, thus using less material in the manufacturing of the tray <NUM> whilst maintaining or improving functionality.

In <FIG>, a side view and bottom view of the tray <NUM> are shown. The tray <NUM> has at least two lateral recessed portions <NUM>, <NUM>, which essentially correspond to the supporting members <NUM> on the support <NUM>. The recessed portions <NUM>, <NUM> are on the opposite side of the tray <NUM> in relation to the central recessed portion <NUM>. As the tray <NUM> is placed on the support <NUM>, the tray will rest on and be held in place by the contact between the portions <NUM>, <NUM> and the support <NUM>.

Furthermore, a first <NUM> of the lateral recessed portions is adapted for restricting motion of the tray in two directions, and a second <NUM> of the lateral recessed portions <NUM>, <NUM> is adapted for restricting motion of the tray in one direction. This is possible since the first lateral recessed portion <NUM> comprises two edges being transverse to the longitudinal direction of the tray <NUM> while the second lateral recessed portion <NUM> only comprises one transverse edge that will limit the motion of the tray <NUM>.

The support of the tray <NUM> may be further facilitated by provision of a rubber coating to the lateral recessed portions <NUM>, <NUM>. The rubber coating will provide increased friction between the tray <NUM> and the support <NUM>, and also reduce any noise that the tray <NUM> may cause due to possible vibrations caused by moving parts in the pump <NUM>. The rubber coating may be a rubber sheet which is applied by an adhesive such as glue or tape, i.e. laminated onto the tray <NUM>. The rubber coating may also be applied in the manufacturing process of the tray <NUM>, for instance as a part of a thermoforming or injection molding process.

The height of the tray <NUM> is between <NUM> and <NUM> in the disclosed embodiment, preferably approximately <NUM> such that it can fit between the pump <NUM> and the support <NUM>.

With reference to <FIG>, the internal components of the tray <NUM> are shown. As can be seen, the tray <NUM> comprises a top portion <NUM> and a bottom portion <NUM>. The top <NUM> and bottom <NUM> portions are connected along a peripheral edge of the tray <NUM>, for instance by means of welding and/or gluing. The top and bottom portions <NUM>, <NUM> may be manufactured in a thermoforming process or in an injection molding process. Other manufacturing processes are however also possible.

The top <NUM> and bottom <NUM> portions form between them a hollow portion <NUM>, in which an insulating sheet <NUM> and/or a electrically heated sheet <NUM> may be arranged. The insulating sheet <NUM> is preferably arranged attached to the top side, i.e. the side facing the top portion <NUM>, of the bottom portion <NUM>. This may be achieved by gluing or by use of other adhesives such as tape. The insulating sheet has a thickness in the range of <NUM> to <NUM>, preferably <NUM> to <NUM> and more preferably <NUM>. The thickness of the insulating sheet may also be varied in relation to the surface area of the tray <NUM>. As the surface area of the tray <NUM> increases, the need for a thicker insulating sheet <NUM> also increases. Thus, a small tray <NUM> may comprise an insulating sheet <NUM> with a thickness that is smaller than the thickness of an insulating sheet <NUM> for a larger tray <NUM>.

The electrically heated sheet <NUM> comprises at least one electrically heated circuit which evenly distributes the heat over the surface area of the sheet <NUM> and onwards to the central recessed portion <NUM> of the tray <NUM>. To facilitate the spreading of the heat from the at least one circuit, the at least one circuit is embedded in a sheet material with high thermal conductivity. The heated sheet <NUM> is attached to the underside (i.e. the side facing the bottom portion <NUM>) of the top portion <NUM> of the tray <NUM>. This may be achieved by gluing or by use of other adhesives such as tape. The heated sheet <NUM> is configured to the heat the central recessed portion <NUM> and at least a part of the inclined edge portion <NUM> to avoid freezing of condensate. The heating temperature of the heated sheet <NUM> may be in the range <NUM> to <NUM>, more preferably approximately <NUM>. This may be regulated by the provision of at least one thermostat <NUM> to the heated sheet <NUM>. The at least one thermostat may be a mechanical thermostat, such as a bimetal thermostat <NUM>, or an electronic thermostat <NUM>, for instance a digital electronic thermostat. The sheet may for instance comprise two heating circuits and two thermostats <NUM>, arranged such that a first thermostat controls a first circuit and a second thermostat controls a second circuit. The first thermostat being arranged to activate the first heating circuit when the temperature drops below approximately +<NUM> and the second thermostat being arranged to activate the second heating circuit when the temperature drops below approximately - <NUM>.

Furthermore, the hollow portion <NUM> is adapted and dimensioned such that when both the electrically heated sheet <NUM> and the insulating sheet <NUM> are arranged within the hollow portion <NUM>, they are spaced apart such that the heated sheet <NUM> does not contact the insulating sheet <NUM>. Thus an intermediate layer of air, between the heated sheet <NUM> and the insulating sheet <NUM>, will further improve the insulating properties of the tray <NUM>.

The top <NUM> and bottom <NUM> portions of the tray <NUM> are preferably made out of a polymer material, such as ABS/PMMA plastic or similar materials. Using a polymer as the material of the tray <NUM> further improves the thermal insulation in relation to metallic materials.

Claim 1:
Drainage tray for collecting condensate from a heat pump adapted to be connected to an indoor unit for providing heat or cooling and regulating an indoor climate, the heat pump (<NUM>) being adapted to be mounted on a support (<NUM>), said support (<NUM>) being mountable to at least one supporting structure to carry the weight of the heat pump (<NUM>) and the support (<NUM>), wherein the tray (<NUM>) comprises a peripheral edge portion (<NUM>) defining a central recessed tray portion (<NUM>) configured to collect condensate, wherein the tray further comprises a condensate outlet (<NUM>) for removing the condensate from the tray (<NUM>), and wherein the tray (<NUM>) is configured to be arranged between an underside of the heat pump (<NUM>) and the support (<NUM>), characterized in that the tray (<NUM>) has an essentially trapezoidal shape corresponding to an L-shaped condenser of the heat pump in a horizontal plane parallel to the underside of the heat pump.