WO1991016587A1

WO1991016587A1 - Heat transfer device

Info

Publication number: WO1991016587A1
Application number: PCT/EP1990/000619
Authority: WO
Inventors: Jan Borg
Original assignee: Jan Borg
Priority date: 1990-04-17
Filing date: 1990-04-17
Publication date: 1991-10-31

Abstract

A procedure for improving the efficiency of a heating/cooling system, the heating/cooling system comprising one or several heater/cooler elements (7) inside which, in an enclosed space (2, 5, 6), is circulated a heat/cooling transfer fluid of which the pressure increases exponentially with increasing temperature. The object of the invention is to improve the efficiency of the heating/cooling system. This is carried out in the invention in that the temperature and pressure of the heat/cool transfer fluid contained in the heater/cooler element (7) are varied by switching the heating/cooling of the heat/cooler transfer fluid alternatingly on an off.

Description

HEAT TRANSFER DEVICE

The present invention relates to a method and an apparatus for improving the efficiency of a heating and cooling system in same boxes with compressor and without as well which may comprise one or several heater/cooler apcaratuses inside which is circulated a heat transfer fluid.

The prior art comprises radiators inside which is circulated for instance water or vapor, in order to transfer heat to the radiator and further to the ambient air, whereb. the water or vapor is circulated through some kind of heater/coder in order to be heated/cool after having given off heat/cool to the radiator or several radiators. Thus, the water or vapor acts to transport the heat between the heater and one or several radiators, and the heat/cool given off by the water or vapor corresponds to the heat supplied by the heater.

The object ot the present invention is to achieve a method and an apparatus which make it possible to improve the efficiency. in that the energy consumption is less than the heat given off by the apparatus.

The present invention makes use of a fluid which condenses and

evaporates in a closed circuit inside a heater/cooler apparatus, the evaporation being caused by supply of heat.

An advantageous embodiment of the method comprises that the heat is supplied by means of a fluid which itself is heated about 10 % of the time which the apparatus is used.

The apparatus may for instance be a radiator containing a closed circuit for circulation of a fluid, for instance Arcton 22, being at a pressure of for instance 20 to 30 N/cm2. The circuit may comprise one or several loops which are surrounded by ribs or baffles in order to increase the

heat/cooler transfer area. The loops are coupled to an internal heat exchanger, in which heat issupclied to the fluid. The internal heat/cooling exchanger may for instance be a horisontal tube which is closed at both ends and contains a conduit extending longitudinally through the tube. A heating f luid, for instance water having a temperature slightly above the evaporation temperature of Arcton 22 at the existing pressure, for instance 60 oC, flows through the conduit, and heat/cooling is transferred to the Arcton. The loop or loops of the closed circuit is/are coupled to each and of the horisontal tube, at different heigths, and evaporated Arcton will enter the highest end of the loop or loops and rise inside the closed circuit. The vapor will give off heat/cooling and at least partly condense, and the liguid will flow down to the horisontal tube and then the fluid will be transfer to next evaporator unit and give cooling as well. This process will continue as long as a certain amount of the heat is transferred from the conduit. The heat given off by the vapor is transferred through the walls of the tube constituting the closed circuit, and the heat may for instance be

transferred to the ambient air by convection.

The fluid, for instance Arcton 22, inside the closed circuit circulates with compressor or without.

Alternatively to the use of a conduit through the horisontal pipe for supply of heat by means of a flowing fluid can be used another Kind of heating means, for instance an electric heater.

In order to increase the heat/cooling transfer area in contact with the ambient air the tube of the closed circuit may, in a perse know manner, be equipped with ribs or baffles externally.

The apparatus according to the invention can be utilized in a system for instance for house heating/cooling, in which several apparatuses may be coupled in series, whereby the conduit for the flow of of the heat supply fluid runs through all the apparatuses, and means such as a valve may be provided for switching the circulation on and off. Means may also be provided for varying the temperature and pressure of the heat supply fluid.

The efficiency of a heating/cooling system provided with the characteristic features presented in the foregoing has been found to be considerably superior to that before.

In the following, the invention is described more in detail with the aid of an example, referring to the drawing.

Fig.1 presents the vertical section of a radiator appropriate for use in the present invention. Fig.2 presents schematically a house heating/cooling system in which the procedure of tne invention is applied.

Thus, in Fig.1 is presented the radiator or heater element in which the method of the present invention can be applied. The radiator comprises a horizontal heat exchanger in consisting of a tubular container 2 containing a fluid, such as Arcton or equivalent, both in gaseous and liquid form, which evaporates with the aid of a heating conduit 3 passing through the heat exchanger. To the container 2 is connected a heat exchanger element 4, in which the fluid in gaseous form gives off heat to the ambient air and condenses at the same time. The element 4 is composed of a plurality of vertical pipes 5 connected on the top margin of the container 2.

In Fig.1, the pipes 5 have been connected, to the bottom pipes.

Thus, in Fig.2 is presented the radiator or cooler element in which the method of the present invention can be applied. The radiator comprises a vertical coding exchanger in consisting of a tubular container 2 containing a fluid, such as Arcton or equivalent, both in gaseous and liquid form, which evaporates with the aid of a cooling conduit 3 passing through the heat exchanger. To the container 2 is connected a heat exchanger element 4, in which the fluid in gaseous form gives off cooling to the ambient air and condenses at the same time. The element 4 is composed of a plurality of vertical pipes 5 connected on the top margin of the container 2.

In Fig.1, the pipes 5 have been connected, to the top of pipes.

The normal situation was previously that the water/fluid circulates in the system all the time, whereby the surface temperature of the heater/cooler elements 1. has settled on a certain level. In the method of the present invetion, the water/fluid circulation is automatically interrupted with the shut-off valve for a certain period, ofinstance for a few minutes, whereby the water-fluid momentarily heated/cool to a temperature considerably higher than that which itwould have ifitwere circulating all the time. When the water/fluid has reached an appropriate temperature, the valve K. opens and the water isagain allowed to circulate in the cooling elements 2. The fluid causes the Arcton in the heater element to be heated and to evaporate instant aneously. Hereby the surface temperature of the element rises rapidly above the temperature which would have been achieved with continous water/fluid circulation, and it goes down very slowly back to this said temperature. The advantage is gained owing to the pressure of Arcton increasino exponent i al l y in relation to the temperature. In precise measurements which have been carried out, the improvement of efficiency has been indisputable. In one experiment, the surface temperature of the radiator had stabilized at 54 in continuous operation. The radiator was then tipped over on its side, whereby the gaseous arcton could not ascend in the pipe 5 and remained instead in the heat exchanger 1 to be heated further. The radiator was kept lying on its side for three minutes, during which time the surface temperature of the radiator at a given point decreased to 48 whereafter the radiator was pieced upright once more and the arcton could ascend. The sureface temperature of the radiator rose to 60 in one minute and begin thereafter to go down very slowly, reaching the limit of 54 only after half an hour. In this way, the surface temperature of the radiator could be held most of the time over 54 which is mean temperature in a continuously operating radiator.

Naturally, tipping radiators cannot be considered in actual practice, but it was easy to demonstrate by this experiment that a remarkable

improvement in efficiency is achieved with the aid of the invention, seeing that the fundamental principle of the procedure of the invention is the same as in the experiment. The invention is based on increasing the temperature of the freon momentarily considerable above the average temperature.

Measurements have been carried out during use of radiator in accordance with the invention. Heat was supplied in an amount of 0,7 kW. Based on measurements of the velocity of the ambient air upwardly through the radiate, the cross sectional area of the radiator through which the air flowed, and the temperature of the ambient air when coming up above the radlator the output was calculated to 2,45 kW.

Claims

1. A method for improving the efficiency of a heatino/cooling system, which may comrises comprising one or several heating apparatuses inside which is circulated a heat transfer fluid, the or each apparatus being a heat exchanger for transferring of heat from the heat transfer fluid to a surrounding medium, characterized in that the heat transfer fluid is kept at a temperaure approximately corresponding tiits evapotaion temeraure. bv supplying heat to the apparatus, in order to cause that the heat transfer fluid evaporates and condenses when flowing in a closed circuit.

2. A method as claimed in claim 1, characterized in that Arcton, ammonia or another medium is used the heat transfer fluid.

3. A method as claimed in claims 1 or 2. characterized in that the fluid is Arcton 22. which has a pressure of 20 to 30 N/cm2 and is kept at a temperature of 50 to 60 oC while circulating in the circuit.

4. A method as claimed in claim 1, 2 or 3. characterized in that heat is supplied by means of a ρrιmary fluid supplied to a lower region of circuit.

5. An apparatus for performing the method of one or more of the claims 1 to 4, characterized in that it comprises a closed circuit for circulation of a heat transfer fluid, the apparatus being a heat exchanger for transferring of heat/cool from the transfer fluid to a surrounding medium, said apparatus comprising means for supply of heat/cool to the apparatus in order to keep the heat/cool transfer fluid approximately at its evaporation temperature.

6. An apparatus as claimed in claim 5, characterized in that the means for supply of heat is situated at the lower region of the closed circuit, whereby evaporated heat transfer fluid can rise in a first portion of the circuit and condence to cool ing in a second portion of the circuit.

7. An apparatus as claimed in claim 6, characterized in that the dosed circuit comprises a lower heat exchanger for evaporation of the heat transfer fluid, the remainder of the circui t being one or several tubes, each of which being connected to the heat exchanger.

8. An apparatus as claimed in claim 7, characterized in that tne lower heat exchanger comorises a jacket which surrounds or contains a heater element, wherein the space between the jacket and the heater element is a part of the closed circuit.

9. A heat system, characterized in that it comprises several apparatuses as claimed in one of the claims 5 to 8. coupled together by means of a conduit for supply of a primary heating fluid to all the apparatuses.