WO2008105733A1

WO2008105733A1 - Part of an air-based heating/ventilation system

Info

Publication number: WO2008105733A1
Application number: PCT/SE2008/050216
Authority: WO
Inventors: Sten Engwall
Original assignee: Semako Ab
Priority date: 2007-02-27
Filing date: 2008-02-27
Publication date: 2008-09-04
Also published as: SE0700502L; SE530915C2

Abstract

The invention relates to a part of an air-based heating system for heating of different room units of levels above the ground floor having different regulation possibilities of both air quantity and temperature of the air for heating of floors.

Description

PART OF AN AIR-BASED HEATING/VENTILATION SYSTEM

Technical Field

The present invention relates to the area of heating of a building in at least one level without direct-acting electricity by means of air as heat carrier.

Background of the Invention

The use of air as heat carrier is an economically attractive and aesthetically pleasing way to heat a dwelling, which has not been possible without radia- tors in above the ground level in small houses.

However, since the air cannot carry any greater amount of energy, the systems have previously been based on partial recirculation of already heated ventilation air, i.e., all of or portions of the used air, which contains different particles that have been carried into the dwelling, has been reheated to subsequently be fed out again. Nowadays, it is known from numerous studies of our indoor climate that the air is unhealthy already without recirculation. Thus, an air-based system with reheating of exhausted air is entirely unacceptable.

The Current Scope of the Problem The National Swedish Institute of Public Health has in a publication ISSN

1104-358X and ISBN 91-88564-15-0 entitled VAR DALIGA INOMHUSLUFT (Our bad indoor air) named not less than 577 articles, reports and theses about this matter, 187 ones of which were published in 1993.

In a preface, it is even suggested that a proposal of a national gathering is made, similar to the one when TB in the 20's and 30's of last century should be eradicated!

The problems with the bad indoor air primarily emanate from our mechanical ventilation systems. These consist of tubings, fans, sound-absorbers and filters. In horizontal tubes, dirt is deposited in spite of the relatively high air velocity. In principle, the filters become dirty immediately after cleaning. Neither fans nor sound-absorbers have a detrimental effect.

In the invention according to the Swedish patent SE 468441 , a one-storied building can both be heated and ventilated by heating outdoor air fed into the substructure. The air heats the uninsulated bottom floor structure. The impact sounds in the bottom floor structure are not heard but in the substructure. By the fact that approx. 80 % of the heat is supplied via the floor and the rest by the fact that the heated air in the substructure that also is brought up as ventilation air, the system may be used also in climates having very severe cold. In the substructure, the heated air is stratified with the warmest closest to the underside of floor so as to then decrease with 1 ⁰C per 30 cm. The dirt particles that enter from the outside are deposited in the substructure and end up on a radon cloth, which covers the bottom of the substructure. The air in the substructure has a very low air velocity in comparison with conventional ventilation sys- terns, since the gap that brings up air from the substructure to the dwelling part has an area many times larger than the filter to be passed by all air in usual ventilation systems.

With a low air velocity, this co-operates with gravitation and thermals into an efficient sedimentation and self-purification of the air without filter. A measure of how well the air is cleaned is that if the house is heated with the inside part 2 of an exhaust-air heat pump 1 , which is placed in the substructure and mounted near the underside of floor, it has turned out that the filter, which when the inside part in the usual case is placed in the dwelling area is recommended to be cleaned once a month, has not become dirty after one year as a consequence of the location in the substructure. For noise reasons, the floor structures have to be insulated in floor levels above the ground floor. This has made it difficult to heat more than the ground level. The floor structure does then not let through the heat, and the energy in the ventilation air is not enough to heat upper levels. For comfort reasons, the temperature of the ventilation air should not be raised.

Fresh air to the substructure is fed through the duct 9 and the amount is regulated by the fan 9B. When the valve 9A is open, the air is brought directly to the substructure space. When it is shut, the supply air is brought to the substructure via the heat exchanger 7 in the substructure space. In a known way, the air in the substructure space is fed as the ventilation air of the house via a gap between the floor structure and external wall in the ground level. The used air, the so-called exhaust air, is fed out of the house via the heat exchanger 7 to the underside of the outdoor-air heat pump 1 as extract air to make use of the energy of the exhaust air that is left after the heat exchanger. By shutting the valves 7A and 8A on each side of the heat exchanger so that the air passes past the same, all energy is left in the exhaust air and is then supplied to the air heat pump 1.

By feeding the exhaust air sometimes directly and sometimes indirectly via the heat exchanger, it can be shown to what extent the heat exchanger contributes to energy saving. In a heat exchanger in which the supply air is heated, no more energy can be recovered than a part of the difference between the temperature of the outdoor air that is fed into the heat exchanger and the temperature of the exhaust air.

The Object of the Invention

The present invention aims at being able to heat all floor levels of a building, preferably small houses, by an air-based system including adjustable heat in the bedrooms of the upper level. The primary heat is obtained from the floor and the remaining by the ventilation air for a desired temperature. The technical apparatus should be as simple as possible but is characterized by a very low energy consumption

An Additional Object is to Show: An outdoor-air heat pump can collect energy from air, i.e., extract down to degrees below freezing. If exhaust air exits the house without passing a heat exchanger, more energy is made use of from the mixture between extract air and outdoor air than the energy a heat exchanger can recover. Conclusion: a heat exchanger is withdrawn from the system.

Description of the Invention

The previously invented system for heating the ground-level floor of a dwelling has by the present invention that in the description shows now has the entire house can be heated in a very energy-saving way. The heat in levels above may even be regulated in different rooms, e.g., in bedrooms where the desires vary from person to person. In the heating system, requirements are included that in the dwelling part, there should not be any horizontal piping that may collect dust by sedimentation in the pipes. The system for heating to the floors of upper levels is therefore made closed, i.e., the same air circulates. Brief Description of the Drawing

Fig. 1 is a schematic section through a building provided with an air-based heating system according to the invention.

List of the Reference Numerals of the Figure:

1 the outdoor part of the outdoor-air heat pump

2 the indoor part of the outdoor-air heat pump

3 fan 4 insulation in upper floor structure

5 vertical duct from floor structure directly to substructure or alternatively to closed air circuit

6a

6b valves open at closed air circuit 7 heat exchanger

8 exhaust air from the two levels of the house directly to the outdoor-air heat pump or indirectly via the heat exchanger

9 outdoor air directly to the substructure or via heat exchanger 9A valve 9B fan

10 fan

11 tube

12 radiator

Description of the Invention

In the present invention, not only the desired temperature on the floor of upper levels is attained, but the same may be regulated individually in, e.g., different bedrooms of an upper level. In the following cases, the valves 6A and 6B of the tube 11 are opened toward the substructure space. Clean air is most suitably collected from the substructure near the underside of the floor structure where it is cleanest, and is fed by the fan 3 in the duct 5A into a particular space f4 above the insulation and floor structure and from there back to the substructure via the duct 5B to the substructure space. By the amount of air that circulates, the temperature of the floor of upper level is regulated. This is attained by the fact that the duct fan 3 is speed controlled by manoeuvring from, e.g., bedrooms of an upper level.

The fan 3 does not affect the set pressure difference with positive pres- sure in the substructure and negative pressure in the dwelling part.

Alternatively, this may be effected via a closed system. In this case, the valves 6A and 6B are shut so that air only can circulate up to the floor structure and back via the tube 11. The air in the closed system is heated indirectly by the heat from the heat pump. Incidental heat gain may also be effected by a heater battery in the tube.

In the closed system, it is the same air that circulates; hence, it follows that no further sedimentation can occur than the amount of particles contained in the system from the beginning.

Since the altogether predominant heating comes from the floor and a neg- ligible part from the ventilation air, the major portion of the energy is recovered from the exhaust air outside the house body as in the case air is directed past the heat exchanger.

Claims

1 Air-based heating system allowing it to embrace upper levels of a small house, characterized by piping 5 for a variable amount of air to and from inter- mediate floor structures and a heated substructure space.

2 Air-based heating system according to claim 1 , but characterized in that the piping 5 consists of a closed system including a variable amount of circulating heated air.

3 Air-based heating system according to claim 2, but provided with a built-in radiator 12 for variable temperature of air.