GB1566312A

GB1566312A - Heating installation

Info

Publication number: GB1566312A
Application number: GB41187/76A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1976-10-05
Filing date: 1976-10-05
Publication date: 1980-04-30

Description

(54) HEATING INSTALLATION (71) I, DIPL.-ING JIRI ELIAS, a Czechoslovakian citizen residing at Im Wingert 18, Zurich, Switzerland, do hereby declare the invention for which I pray that a patent may be granted to me and the method by which it is to be performed to be particularly described in and by the following statement: The present invention relates to a heating installation for heating a room by both radiation and convection in which there is a heating element installed beneath the room floor.

Underfloor central heating systems are known which predominantly deliver the heat by radiation from the floor to a room or space. The utilization of such radiation heaters is associated with certain hygenic and also economical advantage of radiation heating is the freedom from dust contamination.

However, heating by radiation causes little air circulation which, from the hygenic standpoint, may be considered to be disadvantageous. According to certain research results regarding the physiological thermal balance of the human being, there is a limit to the temperature to which the surface of the floor can be raised, this limit being 26"C. With present day technology attempts have been made to deliver more thermal energy through the floor at the region of windows and outer walls. Sometimes it has been necessary, to achieve a desired thermal output, to combine the floor heating with other heating units, or else to exceed the recommended maximum floor surface temperature (26"C).

It is an object of the present invention to provide an improved construction of heating installation which is not associated with the aforementioned drawbacks and limitations of the prior art proposals.

The invention provides a heating installation for heating a room, in which a duct extends across the room beneath the room floor and an elongate heating element extends along the length of the duct in or adjacent the duct, one end portion of the duct having an inflow opening arranged to receive into the duct air from one side of the room, and an opposite end portion of the duct having an outflow opening through which air can pass from the duct to an opposite side of the room from said one side, air entering the duct through the inflow opening being conveyed substantially without loss to the outflow opening and the heating element being effective, in use of the installation to heat the room, to both heat the floor, for radiation heating of the room, and to heat the air in the duct for convection heating of the room by emission of air through the outflow opening.

The invention will be better understood when consideration is given to the following detailed description of an embodiment thereof. The description is to be read with reference to the accompanying drawings wherein: Figure 1 illustrates a heating installation for heating a room; Figure 2 is a view on the vertical section through the line A-A of Figure 1; Figure 3 is a scrap view on the vertical section through the line B-B of Figure 1, illustrating one arrangement of a heating element beneath the room floor.

Figures 4 to 8 are views similar to Figure 3 but showing alternative arrangements of the heating element beneath the room floor.

With reference to the drawings, the heating installation illustrated in principle in Figure 1 serves to heat a room 27 and an adjoining region 28; the region 28 could be another room.

This heating installation comprises a boiler 15 for heating a liquid heat transfer medium transfer medium, an infeed line 17 for infeed of the heat transfer medium to a heating element a return flow line 18 for return of the heat transfer medium to the heat boiler 15, after circulation through the heating element, and a circulation pump 16 for driving the heat transfer medium around the system.

A portion of the heating element is shown in Figures 2 and 3. The heating element comprises an elongate pipe 1 arranged in a duct 9. A plurality of ducts 9 extend in the same general direction across the room 27 beneath the room floor 4, and the pipe 1 follows a serpentine path (as seen in Figure 1) beneath the floor to extend along the lengths of the ducts. Each duct 9 is circular in cross-section (Figure 3). In alternative arrangements the ducts might be oval (Figure 4), semi-circular (Figure 5), rectangular (Figure 6) or triangular (Figure 8) in cross-section. In a further alternative arrangement, illustrated in Figure 7, the heating element extends along the length of the duct 9 adjacent the duct, there being two ducts 9 shown in Figure 7.One end portion 9a of each duct 9 (as shown in Figure 2) has an inflow opening 2, and the opposite end portion 9b of the duct 9 has an outflow opening 3 through which air can pass from the duct to the room 27. The inflow opening 2 of each duct is arranged to receive into the duct air from one side of the room, and the outflow opening 3 is arranged to deliver air to the opposite side of the room. Inflow ports 6 and outflow ports 7 are located in opposite side walls of the room at different levels above the room floor 4, the inflow and outflow ports being connected respectively to the inflow openings 2 and the outflow openings 3 of the ducts 9.

The heat transfer medium flowing through the pipe 1 is cooled therein because it transmits its thermal energy to the surrounding air in the duct 9 and to the material 5 of the floor structure to be heated. The heated air in the duct 9 is circulated by natural convection through the room 27; alternatively forced convection could be employed. Air entering each duct 9 through the inflow opening 2 is conveyed substantially without loss to the outflow opening 3.

The installation is effective to both heat the floor 4, for radiation heating of the room 27, and to heat the air in the ducts 9 for convection heating of the room by emission of heated air through the outflow openings 3. The relative proportions of the heat given for heating by radiation and convection is governed by the circulated quantity of air The room 27 has a volume of 36 m3 (length 5 meters, width 3 meters height 2.4 meters) and a thermal requirement of 1620 kcal/h (45 kcal/m3h). With an average floor surface temperature of 26"C, a room temperature of 18"C, and a coefficient of heat transfer of 8.9 kcal/m2h degree the heat transfer rate from the floor surface is: Q = 8.9 (26 -18) = 71.2 kcal/m2h.The floor surface area is 15 m2 so that the heat transfer rate = 15 x 71.2 = 1068 kcal/h, which is less than the required 1620 kcal/h.

An increase of the pipe heating surface beneath the floor would not be acceptable for a living room, because then also the floor temperature would increase. The missing thermal requirement of (1620 - 1068 =) 552 kcal/h must be furnished by convection.

The required air quantity for an inflow temperature, of air entering the room, of 45"C and a room temperature of 18"C is: 552 V1 = 0.24xl.12(45-l8) = 76 m3/h, where the specific heat of the air is 0.24 kcal/m3 degree.

With an opening cross-section ratio of 0.9 and an elevational difference of 0.7 of the inlet and outlet openings, an inflow opening cross-section of 1.5 x 0.03 = 0.045 m2, a Poisson ratio of 0.6 and an hourly air quantity of 2900 m3/h, the air quantity amounts to: V2 = 2900 x 0.7 x 0.045 = 91 m3/h.

The heating installation enables the room 27 to be heated with optimum conditions for the physiological thermal balance of a human being. There do not exist static air conditions, yet the air flow remains within a comfortable range and ensures a balanced temperature course of the heated room. The adjacent region 28 (which might be a bathroom, or corridor) having a smaller thermal requirement is heated by the return flow of the heat transfer medium. The heating installation can be operated with infeed temperatures for the heat transfer medium of around 90"C which enables the installation to be operated economically.

In an alternative arrangement, an electrical heating element could be employed.

While there are shown and described present preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto, but may be otherwise variously embodied and practiced within the scope of the following claims.

WHAT WE CLAIM IS: 1. A heating installation for heating a room, in which a duct extends across the room beneath the room floor and an elongate heating element extends along the length of the duct in or adjacent the duct, one end portion of the duct having an inflow opening arranged to

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. after circulation through the heating element, and a circulation pump 16 for driving the heat transfer medium around the system. A portion of the heating element is shown in Figures 2 and 3. The heating element comprises an elongate pipe 1 arranged in a duct 9. A plurality of ducts 9 extend in the same general direction across the room 27 beneath the room floor 4, and the pipe 1 follows a serpentine path (as seen in Figure 1) beneath the floor to extend along the lengths of the ducts. Each duct 9 is circular in cross-section (Figure 3). In alternative arrangements the ducts might be oval (Figure 4), semi-circular (Figure 5), rectangular (Figure 6) or triangular (Figure 8) in cross-section. In a further alternative arrangement, illustrated in Figure 7, the heating element extends along the length of the duct 9 adjacent the duct, there being two ducts 9 shown in Figure 7.One end portion 9a of each duct 9 (as shown in Figure 2) has an inflow opening 2, and the opposite end portion 9b of the duct 9 has an outflow opening 3 through which air can pass from the duct to the room 27. The inflow opening 2 of each duct is arranged to receive into the duct air from one side of the room, and the outflow opening 3 is arranged to deliver air to the opposite side of the room. Inflow ports 6 and outflow ports 7 are located in opposite side walls of the room at different levels above the room floor 4, the inflow and outflow ports being connected respectively to the inflow openings 2 and the outflow openings 3 of the ducts 9. The heat transfer medium flowing through the pipe 1 is cooled therein because it transmits its thermal energy to the surrounding air in the duct 9 and to the material 5 of the floor structure to be heated. The heated air in the duct 9 is circulated by natural convection through the room 27; alternatively forced convection could be employed. Air entering each duct 9 through the inflow opening 2 is conveyed substantially without loss to the outflow opening 3. The installation is effective to both heat the floor 4, for radiation heating of the room 27, and to heat the air in the ducts 9 for convection heating of the room by emission of heated air through the outflow openings 3. The relative proportions of the heat given for heating by radiation and convection is governed by the circulated quantity of air The room 27 has a volume of 36 m3 (length 5 meters, width 3 meters height 2.4 meters) and a thermal requirement of 1620 kcal/h (45 kcal/m3h). With an average floor surface temperature of 26"C, a room temperature of 18"C, and a coefficient of heat transfer of 8.9 kcal/m2h degree the heat transfer rate from the floor surface is: Q = 8.9 (26 -18) = 71.2 kcal/m2h.The floor surface area is 15 m2 so that the heat transfer rate = 15 x 71.2 = 1068 kcal/h, which is less than the required 1620 kcal/h. An increase of the pipe heating surface beneath the floor would not be acceptable for a living room, because then also the floor temperature would increase. The missing thermal requirement of (1620 - 1068 =) 552 kcal/h must be furnished by convection. The required air quantity for an inflow temperature, of air entering the room, of 45"C and a room temperature of 18"C is: 552 V1 = 0.24xl.12(45-l8) = 76 m3/h, where the specific heat of the air is 0.24 kcal/m3 degree. With an opening cross-section ratio of 0.9 and an elevational difference of 0.7 of the inlet and outlet openings, an inflow opening cross-section of 1.5 x 0.03 = 0.045 m2, a Poisson ratio of 0.6 and an hourly air quantity of 2900 m3/h, the air quantity amounts to: V2 = 2900 x 0.7 x 0.045 = 91 m3/h. The heating installation enables the room 27 to be heated with optimum conditions for the physiological thermal balance of a human being. There do not exist static air conditions, yet the air flow remains within a comfortable range and ensures a balanced temperature course of the heated room. The adjacent region 28 (which might be a bathroom, or corridor) having a smaller thermal requirement is heated by the return flow of the heat transfer medium. The heating installation can be operated with infeed temperatures for the heat transfer medium of around 90"C which enables the installation to be operated economically. In an alternative arrangement, an electrical heating element could be employed. While there are shown and described present preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto, but may be otherwise variously embodied and practiced within the scope of the following claims. WHAT WE CLAIM IS:

1. A heating installation for heating a room, in which a duct extends across the room beneath the room floor and an elongate heating element extends along the length of the duct in or adjacent the duct, one end portion of the duct having an inflow opening arranged to

receive into the duct air from one side of the room, and an opposite end portion of the duct having an outflow opening through which air can pass from the duct to an opposite side of the room from said one side, air entering the duct through the inflow opening being conveyed substantially without loss to the outflow opening and the heating element being effective, in use of the installation to heat the room, to both heat the floor, for radiation heating of the room, and to heat the air in the duct for convection heating of the room by emission of air through the outflow opening.

2. An installation according to claim 1 in which air is circulated through the duct and the room by natural convection.

3. An installation according to either one of claims 1 and 2 in which inflow and outflow ports in opposite side walls of the room are at different levels above the floor of the room, the inflow and outflow ports being connected respectively to said inflow and outflow openings.

4. An installation according to any one of the preceding claims in which a plurality of ducts extend in the same general direction across the room, and the heating element follows a serpentine path beneath the room floor to extend along the lengths of the ducts in or adjacent the ducts.

5. An installation according to any one of the preceding claims in which the heating element comprises a pipe through which a liquid heat transfer medium can be passed.

6. A heating installation substantially as hereinbefore described with reference to Figures 1 and 2 and any one of Figures 3, 4, 5, 6, 7 or 8 of the accompanying drawings.