Heating systems – Automatic control – Water
Patent
1994-09-07
1996-11-12
Tapolcai, William E.
Heating systems
Automatic control
Water
237 19, F24D 302
Patent
active
055731830
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
This invention relates to a method for heating room space of a building, comprising conveyance of heat from a district heating liquid to a heating liquid of heating circuits for heating the building and the ventilation air or the like. The invention also relates to an apparatus for heating room space of a building.
In district heating plants and boiler plants, the temperature of supply water conducted from the plant is usually 90.degree. . . . 110.degree. C., depending on the plant. The water required for the heating, ventilation and tap water of buildings is generally heated in a heat exchanger, the temperature of the water supplied therefrom to the building being normally 70.degree. . . . 90.degree. C. In a peak load situation, according to which heating networks are usually designed, the temperature of return water conducted from the building cannot normally be dropped below 40.degree. C. The temperature of the district heating return water is thus approximately 50.degree. C. when minimum costs are to be achieved. In view of the investment costs, pumpage rates, heat losses, etc., of district heating networks, it would be advantageous to drop the temperature of the return water even more, but the costs of heat exchangers would increase rapidly even with a small additional drop, as the temperature difference even in the present apparatuses is rather small, about 10.degree. C.
In conventional buildings, the proportion of ventilation in the heating energy consumption of the building is approximately 35 . . . 50%, depending on the type of building and the systems utilized in it. Both the heat losses of the building and the heat requirement of ventilation are directly proportional to the difference between indoor and outdoor temperature, i.e. the ratio between them is approximately constant. The overall heat balance encompasses, in addition, the internal heat evolution of the building (lighting, electric appliances, people, etc.) and hot tap water, which are both independent of outdoor temperature and have opposite effects. The proportion of ventilation varies thus very little with changes in the outdoor temperature.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a method by means of which the temperature of district heating return water can be dropped more than in known apparatuses without significant extra investments. The method of the invention is characterized in that one of said liquids is arranged to flow in such a manner that it conveys heat first to the heating of the building and thereafter to the heating of the ventilation air.
The basic idea of the invention is to connect the heat supplies for heating and ventilation in series in such a manner that in the first step the heat requirement of heating is met at a higher energy level, and in the second step the heat requirement of ventilation is met at a lower energy level. This can be achieved either by circulating the heating water of a building first through the heating system of the building and then through heat exchangers of the ventilation system, or by circulating the district heating water first through the heating system and then through the heat exchanger of the ventilation system.
The advantages of the invention are particularly obvious when heat is conveyed from exhaust air of a building to supply air by means of a heat recovery circuit.
In the first step, the circulating water can be cooled down to about 40.degree. C. and the district heating return water to about 50.degree. C., as stated above. In the second step, the heating water of the system can be cooled even below 0.degree. C. according to the invention, with the result that the temperature of the district heating return water can be dropped to 20.degree. . . . 30.degree. C. Thus, the capacity of the district heating network can be increased by about 50%, or the investments can be reduced by about 35%. The pumpage rate can be reduced by about 30 . . . 35%, and the heat losses of the return water can be reduced to below hal
REFERENCES:
patent: 3890787 (1975-06-01), Margen
patent: 4232657 (1980-11-01), Killorin
patent: 4347972 (1982-09-01), Hillerstrom et al.
patent: 4671459 (1987-06-01), Stapensea
patent: 5226594 (1993-07-01), Swenson
patent: 5347825 (1994-09-01), Krist
ABB Flakt AB
Tapolcai William E.
LandOfFree
Method and apparatus for heating building and ventilation air does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for heating building and ventilation air, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for heating building and ventilation air will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-557012