|Title of Invention||
''SOLAR HEAT PIPE COLLECTOR''
|Abstract||A solar heatpipe collector for water heating comprising an insulated collector box (1) having a fin tube absorber panel (2) with plurality of riser tube (3) and a bottom header (5) characterized in that top header (4) of said absorber panel (2) is constructed as tube-in tube heat exchanger with utility water flowing through the condenser header (6).|
|Full Text||The present invention relates to a solar heatpipe collector and more particularly to a flatplate solar collector module converted to work on thermosyphon heatpipe principle.
The existing standard flat plate collector generally
produced in India, for water heating essentially consists of
2 copper fin tube absorbers of 2m area, aluminium collector box
insulated with glass wool/rock wool and a glass cover for allowing the solar radiation. All the riser tubes of the absorber plate are parallelly connected to the top as well as the bottom header.
The cold water from the storage tank the entry collector from the bottom header and passes through the riser tubes collecting the heat from the absorber fins. The heated water comes out from the top and goes back to the storage tank. Under normal solar radiation the standard collector heats 100 litres of water per day upto 55 to 75 C.
Using a heatpipe as a heat trnsfer element can quickly transfer the solar energy collected by a heat collector to a water tank, which improves the problem of slow heat transfer in conventional solar collectors that rely on natural cyclical transfer of heat.
US Patent No. 4416261 to van der Aa, us Patent No. 4067315 to Fehlner teach solar collectors, US Patent No. 4421,100 to Ying-Nien Yu a thermosyphon heatpipe hot water appliance is
disclosed. In US Patent. No. 4438759 to Kitajima, et al, a heatpipe type solar collector is described. In these prior art devices, the solar heat collected by the heat absorber portion is transferred by upper connecting tubes to the heat release portion predisposed in the water tank. In the US Patent No. 5931156 to the inventors chih-yao wang, wei-yih W.n, yang-yih Ha and Tien-yuan hi, for the integral Heatpipe type solar collector, the water is heated by the working fluid vaporized during the day. The tank and the collector are integrl and the tank is insulated during the night by vacuum insulation. This is essentially a storage type collector.
The Indian Patent application No. 706/DEL/99 submitted by the inventor himself for Solar Geyser, also works on thermosyphon heatpipe principle where the collector and the storage tank are integral. This is also essentially a storage type solar collector.
There are disadvantages associated with the present system of solar collector.
The main disadvantages is that as the utility water has to pass through the riser tubes scale formation occurs in them. Sometime where there is hard water, the riser tubes get choked and the collector stops functioning.
Therefore, the main object of the present invention is to provide a solar heat pipe collector in which scale formation in the riser tube is considerably reduced or completely eliminated.
Another object of the present invention is to provide a solar heat pipe collector which works on thermosyphon heatpipe principle having exceptionally rapid conductivity and better performance and modular in design.
Yet another object of the present invention is to provide compact design in comparison to the existing collector.
A further object of the present invention is to provide a heat pipe collector which is modular in design and can be easily coupled in series or parallel for higher capacity water heating system.
According to the present invention there is provided a solar heat pipe collector for water heating comprising an
insulated collector box having a fin tube absorber panel with
plurality of riser tube a to 6 leaver and a bottom header characterized in
that top header of said absorber panel is constructed as tube-
in tube heat exchanger with utility water flowing through the condenser header.
The nature of the invention, its objective and further advantages residing in the same will be apparent from the following description made with reference to non-limiting exemplary embodiments of the invention represented in the accompanying drawing.
Figure 1 shows schemtically the solar heat pipe collector.
DETAILED DESCRIPTION OF THE INVENTION:
According to this invention is provided a solar heatpipe co Mect or for watar heating comprising an insulated collector box (1) having a fin tube absorber panel (2) with plurality of rieer tube (3), a top header and a bottom header (5) characterized in that top header (4) of taid absorber panal (2) is constructed as tube-in tube heat exchanger with utility water flowing through the condenser header (6).
Solar water heating systems bated on thermosyphon princlple have become popular nowadays as they are simple easy to operate and are maintenance free. The heatpipe collector is very well suitable for thermosyphon systems as it can be connected in series without much pressure drop in the system. Thus N gives higher temperature difference between the inlet and outlet of the collector bank, producing higher thermosyphonic head which is essential for better performance.
The solar heatpipe collector is as shown in Fig 1 Is based on tharmosyphon heatpipe principle. Heatpipe is a device, which transports heat from one end to tha other and of a tuba by evaporation and condensation of a working fluid. Since the latent heat of evaporation is large, considerable quarkkles of heat can be transported with a small tamparatura difference, Whan tha condense return to the evaporator is due to gravity,it is known as tharmosyphon heat pipe.
The heatpipe collector is similar to the existing one except for the top header (4) which is converted to a heat exchanger, and the whole absorber panel is made to work on the thermosyphon heatpipe principle. The collector as shown In the fig. 1.essentiality consists of fin tube absorber panal (2) with bottom header (8), top header (4), condenser header (6), insulated collector box (1), and a glass sheet (7) on the top of the collector.
The absorber panel (2) is selectively coated and the riser tubes (3) are brazed to the top (4) and bottom headers (5). The total absorber panel is pressure tested, evacuated and charged with required quantity of working fluid to operate on heatpipe principle.
Under normal solar insolation, the selectively coated absorber fin (2) absorbs the radiation and gets heated and transmits the heat to the working fluid through the riser tubes (3). The working fluid gets vapourised and rises to the top header (4) where it condenses by exchanging the heat with the utility water passing through the condenser header (6). The possibility of scale formation in the riser tubes (3) is totally eliminated as the utility water does not pass through. Thus the risk of scale formation is restricted to only on the inside wall of the condenser header (6), where the maintenance is easy. The solar heat pipe collector built for the first time by BHEL Corporate, R& D, Hyderabad has the capacity to heat 100 litres of water per day upto the range of 50 to 70 C depending on the available solar radiation. It is compact, reliable, efficient, economical and durable compared to the existing standard collector. The heatpipe collector with 1.5m9
absorber area, is compact in comparison to the existing
2 collector, whose absorber area is 2m . The temperature rise
per day is about 21 C/m in comparison to the 19 C/m in case of standard existing collector.
Unlike in the existing collector, the pressure drop accross heatpipe collector is less as the utility water has to pass through only a single header of one inch diameter.
The system cost with the heatpipe collector of our invention is about 20% less compared to the standard existing system as it is compact and the interconnecting insulated pipelines are minimised.
The heatpipe collector of our invention has a consistent performance and better life as there is no scale formation is riser tube.
The invention described hereinabove is in relation to a non-limiting embodiment and as defined by the accompanying claims.
1. A solar heatpipe collector for water heating comprising an insulated
collector box (1) having a fin tube absorber panel (2) with plurality of riser
tube (3), a top header and a bottom header (5) characterized in that top
header (4) cf said absorber panel (2) is constructed as tube-in tube heat
exchanger with utility water flowing through the condenser header (6).
2. The solar heatpipe coNector as claimed in claim 1 wherein the collector is
covered on the top with a glass sheet (7).
3. The solar heatpipe coNector as claimed In claim 1 wherein the collector based on thermosyphon heatpipe principle is modular In construction and can be ampled In series or paraHel to the top headers without running any external connecting lines between top and bottom headers of the adjacent collectors for higher capacity water heating system.
4. The solar heatpipe collector as claimed in claim 1 wherein the absorber panel (2) is selectively coated and the riser tubes (3) are brazed to the top and botom headers (4,5).
5. . A solar heat pipe collector as herein described and illustrted with accompanying drawings.
|Indian Patent Application Number||70/DEL/2001|
|PG Journal Number||13/2008|
|Date of Filing||29-Jan-2001|
|Name of Patentee||BHARAT HEAVY ELECTRICALS LTD,|
|Applicant Address||BHEL HOUSE, SIRI FORT, NEW DELHI-110 049,|
|PCT International Classification Number||F24J 2/00|
|PCT International Application Number||N/A|
|PCT International Filing date|