Ground circuit in a low-energy system

Abstract

The present invention relates to a ground circuit in a low-energy system, said ground circuit comprising a connection pipeline (3), collection pipe system (2) and a return pipeline (4) for circulating a transfer fluid. The ground circuit is utilized for transferring thermal energy recovered from its surroundings, for instance, to a heat pump (5) or the like. The present ground circuit collection pipe system (2) is characterized by consisting of a hollow profile (6) arranged to be a coil, whereby the hollow profile is connected at its first end to a connection pipeline (3) for conveying the transfer fluid along the hollow profile from the first coil end to the second, and at the second end of the coil the second end of the hollow profile is connected to the return pipeline (4) for conveying the transfer fluid from the hollow profile towards the place where used. At the opposite ends of this hollow profile there are advantageously arranged means for controlling the fluid flow provided therein.

Description

BACKGROUND OF THE INVENTION[0001]The invention relates to a ground circuit in a low-energy system in accordance with the preamble of claim 1. The invention also relates to a method for recovering energy in accordance with claim 16.[0002]A ground circuit and a method of this kind are utilized, in particular, in systems where energy—as well heat as cold—is transferred with a terminal device from ground, rock or water by the intermediary of a transfer fluid. Said terminal device may be as well a heat pump as an air conditioning radiator.[0003]In this context the low-energy system refers to a system whose energy source has a low temperature, and most conventionally this temperature may be in the range of +2 to +10° C. In this specification, the energy content generated by an energy source, such as ground, rock or water, will be referred to as low energy. Utilization of the low energy of ground, rock or water has generally referred to heating of a building or tap water by employing a hea...

AI Technical Summary

Benefits of technology

[0012]The invention is based on the idea that the physical length a ground circuit takes in the environment may be substantially reduced by utilizing a coiled pipe in the structure of the ground circuit. A hollow profile encircling an internal cavity formed by a pipe of this kind may provide up to a 50-metre long collection pipe system for one metre of pipe in longitudinal direction. By arranging these coils nested one inside the other it is possible to further increase the total length of the collection pipe system. Each coil being tubular in structure, there is provided a ground circuit solution that is easy to manufacture and reliable in operation.

[0014]Of the large amount of hollow profile arranged for the length of pipelines constituting the collection pipe system a considerably shorter pipe than before will suffice for implementing a collection circuit, whereby both installation and maintenance work becomes significantly easier.

[0015]By arranging several coiled collection pipe systems nested one inside the other it is possible to provide a multi-pipe collection circuit that is particularly well suited for flowing water and that is able to utilize effectively the energy content of water conveyed therein and flowing therethrough.

[0016]In particular, a multi-pipe collection pipe system consisting of nested coils is well suited for utilization, for instance, in the vicinity of flowing water such that the collection pipe system is connected at its opposite ends to vertical wells, into which a flow of the nearby water body is conveyed. Maintenance of the collection pipe system that is located on dry land and has a closed outer surface becomes simpler, when it is possible to use vertical wells for servicing the exchanger, for instance, for washing with pressure washers. In addition, the vertical wells enable flow rate control in the collection pipe system.

Problems solved by technology

A ground circuit of this kind requires a large surface area to obtain a sufficient efficiency, and consequently it can only be used on large plots of land.

To place a horizontal pipe system in the ground requires that an extensive pipe trench system be dug throughout the length of the ground circuit, whereby the placement thereof in a finished courtyard area or park, for instance, is difficult without causing serious damage to the root systems of plants and trees.

However, a liquid-filled pipe is lighter than the surrounding water, and consequently it tends to rise towards the surface.

Irregularly risen portions of the collection pipe system may produce in the collection pipe system air pockets that hamper the circulation of the transfer fluid.

The pipe system installed in the bottom of the water body is also more vulnerable to breakage than the one dug in the ground.

For instance, an anchor of a boat or a similar device may get caught in the pipe system and break it.

This portion containing loose material increases the cost of a heat well, because it must be furnished with a special protective pipe which prevents the well from collapsing.

In addition, energy yield from the loose material portion is poorer than from the rock portion, and consequently the well is to be made deeper, or there is to be made a plurality of wells side by side in the loose material.

Because the construction of a collection circuit is labour intensive, the costs incurred have often been high, which for its part has curbed the interest in low-energy systems.

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