What is an absorber plate?
What is a collector plate?
What is the air gap between the absorber plate and the glass cover of a solar collector?
How long does it take for a collector plate to peel off?
What is copper tubing used for?
How to selectively prepare a surface?
What is the problem with aluminum tube in sheet?
See 4 more
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What is absorber plate in solar collector?
A solar absorber plate is the metallic material right behind the glass in a collector. It is responsible for transferring the solar energy into the collector using the risers that are connected to it.
What is the purpose of the insulation at the bottom of the flat plate collector?
Insulation covering sides and bottom of the collector to reduce heat losses.
What are the parts of a flat plate collector?
Flat-plate collectors are an extension of the basic idea to place a collector in an 'oven'-like box with glass in the direction of the sun. Most flat-plate collectors have two horizontal pipes at the top and bottom, called headers, and many smaller vertical pipes connecting them, called risers.
What is the function of metal flat plate in solar panel?
A Flat Plate Collector is a heat exchanger that converts the radiant solar energy from the sun into heat energy using the well known greenhouse effect.
What is absorber plate?
Absorber plate: The absorber plate is made from copper, stainless steel, or plastic. The whole surface of absorber is enclosed with black materials with greater absorbance. A selective coating on the copper absorber plate will increase the absorptivity. This is of copper/aluminum/mild steel of thickness 0.20 mm.
How can you increase the efficiency of a flat plate collector?
The collector efficiency is obtained here, without reflector as 51%, and with reflector as 61%. Thus, the overall efficiency of the flat plate solar collector is increased approximately 10% by using the reflector with the collector.
What are the main components of flat plate solar collector in the from PPT?
Solar Air Collector The difference is that instead of liquid fluid, an electric fan pumps air through the collector. The main components are: absorber plate (1), glass cover (2), insulation (3), casing (4), and exhaust fan (5).
Where are flat plate solar collector used?
Flat-plate collectors are used for residential water heating and hydronic space-heating installations. Figure 2 shows a schematic drawing of the heat flow through a collector. The question is, how to measure its thermal performance, i.e. the useful energy gain or the collector efficiency.
What is a heat pipe in flat plate collector?
Basically, a HPFPC consists of a number of heat pipes which play the role of heat carriers. Instead of using a cylindrical glass covers (basic form used in evacuated tube collectors), the idea is to cover the heat pipes arrangement with a flat plate glass cover.
What is the working principle of a flat plate collector?
The working of a flat plate collector (FPC) involves the transfer of heat or thermal energy. The operating medium exchanges heat from the sun's rays. The heat-absorbing plate of the collector is exposed to sunlight. As the sun rays hit the flat plate surface, a portion of their energy is transformed into heat.
What is glazing in flat plate collector?
Glazing is the top cover of a solar collector. It performs three major functions in particular: to minimize convective and radiant heat loss from absorber, to transmit the incident solar radiation to the absorber plate with minimum loss, and to protect the absorber plate from outside environment [
What is a flat plate?
Medical Definition of flat plate : a radiograph especially of the abdomen taken with the subject lying flat.
What factors affect the performance of a solar flat plate collector?
Water is considered in the present study as the working fluid. Other factors affect the efficiency of the collector as the water rate of flow, selective coatings of the front surface of the absorber, heat losses by convection and radiation, the surface absorptivity of the surface.
What type of tubing is used inside a flat plate collector?
There are two main types of tubes that are used inside the collector which are glass-glass and glass-metal. The glass-glass version uses two layers of glass fused together at both ends. The double glass tubes have a very reliable vacuum but reduce the amount of light that reaches the absorber inside.
Which part of flat plate collectors is coated in black?
Absorber plateWhich part of flat plate collectors is coated in black? Explanation: Absorber plate is usually metallic or coated in black surface which is used for absorbing radiation energy. The absorber plate's coating directly affects how efficient the collector is.
Where are flat plate solar collector used?
Flat-plate collectors are used for residential water heating and hydronic space-heating installations. Figure 2 shows a schematic drawing of the heat flow through a collector. The question is, how to measure its thermal performance, i.e. the useful energy gain or the collector efficiency.
EFFECT OF ABSORBER PLATE MATERIAL ON FLAT PLATE COLLECTOR EFFICIENCY ...
ABSTRACT The study was conducted to investigate the effect of absorber plate material on the efficiency of heat-absorbing flat plate collectors.
Absorbing Plate - an overview | ScienceDirect Topics
Absorbing plate: It is suitably treated or painted, such as to absorb as much as possible the incident solar radiation.. Heat transfer area: The area (tubes or channels) through which the absorbed energy is transferred to a fluid (liquid or air).. Top cover(s) that are transparent to solar spectrum: They are placed over the solar absorber surface to reduce convection and radiation losses to ...
Flat Plate Collector Working Principle. How Does It Work?
This type of thermal solar panel has a reasonable cost/effectiveness ratio in moderate climates and are well suited to a large number of thermal applications, such as:. Space heating. It can be used to heat water for a pool.. Support for solar water heating systems - domestic hot water (). Preheating of industrial fluids. How Does a Flat Plate Collector Work?
What is series absorbing plate?
Series absorbing plate configuration: it is composed of a single continuous circuit with a low volume of circulating water and a higher thermal jump, with good performance.
What Advantage Do Glazed Flat Plate Collectors Have?
To achieve this, the transparent cover of the collector generates a greenhouse effect.
What is the function of a glazing cover?
The glazing cover has the function of isolating the solar collector from external environmental conditions and allowing solar radiation to pass through. This cover is what causes the greenhouse effect.
What happens when solar radiation hits a solar collector?
Solar radiation falls on the heat-absorbing plate of the collector. When incident solar radiation hits the absorbing plate surface, part of its energy is converted into heat. Consequently, the temperature of the solar collector increases.
What is flat plate solar collector?
The flat plate solar collector is a type of solar thermal panel whose objective is to transform solar power into thermal energy.
Why does the temperature of a fluid rise when passing through a collector?
If we pass a fluid inside the collector, the fluid temperature rises because part of the absorbing plate heat is transferred to the liquid according to the first and second laws of thermodynamics. However, the rest of the energy is still lost in radiation to the outside environment.
What temperature is a flat collector?
Depending on the outside temperature, it is generally used in swimming pool heating systems but can sometimes be used as a hot water heating system in hot countries. In temperate areas, the operating temperature is generally below 30 degrees Celsius.
Overview
It is used to absorbed solar energy, convert it into heat, and then to transfer that heat to stream of liquid or gases. They use both direct and diffuse solar radiations, do not require tracking of the Sun, and require little maintenance. They are mechanically simpler than concentrating collectors.
Components
Glazing consists of one or more sheets of glass or other radiation-transmitting material.
Types
Various types of solar collectors: (A) flat-plate, (B) parabolic trough, (C) evacuated tubes, (D) unglazed EPDM collector, and (E) perforated plate.
Solar Air Collector
Solar air collectors have the operating principles similar to FPCs (Fig. below).
Energy Balance
In Fig. below is illustrated energy balance of a standard FPC. From total solar radiation IT incident on glass cover, a part (τ · IT) determined of transmittance τ reaches the absorber plate where it is transformed in heat.
What are the advantages of flat plate collectors?
Some advantages of the flat-plate collectors are that they are: 1 Easy to manufacture 2 Low cost 3 Collect both beam and diffuse radiation 4 Permanently fixed (no sophisticated positioning or tracking equipment is required) 5 Little maintenance
What is the main component of a flat plate solar collector?
These are the main components of a typical flat-plate solar collector: Black surface - absorbent of the incident solar energy. Glazing cover - a transparent layer that transmits radiation to the absorber, but prevents radiative and convective heat loss from the surface. Tubes containing heating fluid to transfer the heat from the collector.
What is the best angle for a solar collector?
Flat-plate collectors are installed facing the equator (i.e. South oriented in the Northern hemisphere and North oriented in the Southern hemisphere). The optimal tilt of the collector plate is close to the latitude of the location (+/- 15 o ). If the application is solar cooling, the optimum installation angle is Latitude - 10 o, so that the solar beam is perpendicular to the collector during summertime. If the application is solar heating, the optimum installation angle is Latitude + 10 o. It was found however, that for year-round hot water application, the optimum angle is Latitude + 5 o, which provides somewhat better performance during winter, when the hot water is more needed (Kalogirou, 2009)
What temperature does a flat plate collector work at?
The flat-plate systems normally operate and reach the maximum efficiency within the temperature range from 30 to 80 o C (Kalogirou, 2009), however, some new types of collectors that employ vacuum insulation can achieve higher temperatures (up to 100 o C). Due to the introduction of selective coatings, the stagnant fluid temperature in flat-plate collectors has been shown to reach 200 o C.
How does solar radiation affect the fluid in the tubes?
The solar radiation is absorbed by the black plate and transfers heat to the fluid in the tubes. The thermal insulation prevents heat loss during fluid transfer; the screens reduce the heat loss due to convection and radiation to the atmosphere. Credit: Mark Fedkin (modified after Duffie and Beckman, 2013)
How does a solar collector work?
The overall idea behind this technology is pretty simple. The Sun heats a dark flat surface , which collect as much energy as possible , and then the energy is transferred to water, air, or other fluid for further use. These are the main components of a typical flat-plate solar collector:
Can phase change liquids be used with flat plate collectors?
Phase-change liquids can also be used with flat-plate collectors. Some refrigerants are included in this group of fluids. They do not freeze, which eliminates troubles explained above for water, and, due to their low boiling point can change from liquid to gas as temperature increases.
What is an absorber plate?
Absorber plates are flat, corrugated, or grooved plates, to which the tubes, fins, or passages are attached.
What is a collector plate?
The collector or absorber plate is usually the most complex and expensive component of the collector, the remaining parts being freely available in the trade and in mass production for other purposes. This discussion concerns the liquid-heating type only, which may either be of the Tellier (double sheet) type or of the sheet and tube type.
What is the air gap between the absorber plate and the glass cover of a solar collector?
The air gap separating the absorber plate and the glass cover in a solar collector has a width across the gap of 2 cm. At a particular time the absorber plate temperature is 60C and the glass cover is at 30C. Find the Rayleigh number for the air gap based on the gap width.
How long does it take for a collector plate to peel off?
Without this the repeated thermal expansion and contraction of the surface of the collector plate may cause the paint to peel off in less than a year. Several types of baked-on black finishes are available. The collector plate may also be coated with a selective black coating produced chemically or by electroplating.
What is copper tubing used for?
Copper tubing has been used in most solar water heating installations , and is becoming increasingly popular in potable water systems, although on a first-cost basis it is more expensive than most competing materials. The direct use of water in a flat plate collector poses other problems.
How to selectively prepare a surface?
There are several different ways in which selective surfaces can be prepared, depending on the physical principle involved. Tabor (32) has been concerned with finely divided metals deposited on polished metal undersurfaces; other methods include the deposition of thin semiconductor layers which absorb the short wavelengths but not the long, thus allowing the metallic undersurface to maintain its low emissivity. Surfaces may also be given a controlled degree of roughening so that only the absorptivity for short wavelengths is increased. Surfaces with large (relative to all radiation wavelengths) V-grooves can be arranged so that radiation from near normal directions to the overall surface will be reflected several times in the grooves. An effective α /e of 9 with α = 0.9 has been suggested (19).
What is the problem with aluminum tube in sheet?
The one major problem encountered with aluminium tube-in-sheet is the corrosion which generally occurs when untreated water comes into contact with bare aluminium. The Showa Aluminium Co. of Japan has a U.S. patent on the use of zinc powder in the special “ink” used in the Roll-Bond process and this produces the equivalent of a galvanizing action on the water passages which, according to Showa, makes them entirely resistant to corrosion.
Overview
Components
- Glazing consists of one or more sheets of glass or other radiation-transmitting material.
- Tubes, fins, or passages to conduct or direct the HTF from the inlet to the outlet.
- Absorber plates are flat, corrugated, or grooved plates, to which the tubes, fins, or passages are attached. The plate may be integral with the tubes.
- Headers or manifolds to admit and discharge the HTF.
Types
- Glass has been widely used to glaze FPCs because it can transmit as much as 90% of the incoming shortwave solar radiation while transmitting very little of the longwave radiation emitted outward from the absorber plate. Glass with low iron content has a relatively high transmittance for solar radiation (0.85–0.90 at normal incidence). Plastic films and sheets also have high shor…
Incident Angle of Transmittance and Absorptance
- Variation With Incident Angle of Transmittance and Absorptance Antireflective coating and surface texture can improve transmission significantly. The absorber plate absorbs as much of the radiation as possible through the glazing, while losing as little heat as possible up to the atmosphere and down through the back of the casing. The absorber plate transfers retained hea…
Insulation Materials
- Main Properties of Insulation Materials FPC is usually permanently fixed in position and requires no tracking of the Sun. The collectors should be oriented directly toward the equator, facing south in the northern hemisphere and north in the southern. The optimum tilt angle of the collector is equal to the latitude of the location with angle variations of 10–15°C, more or less depending o…
Solar Air Collector
- Solar air collectors have the operating principles similar to FPCs (Fig. below). The difference is that instead of liquid fluid, an electric fan pumps air through the collector. The main components are: absorber plate (1), glass cover (2), insulation (3), casing (4), and exhaust fan (5). This collector type is not very common in Europe (covers only 1–2% of the solar liquid collector mark…
Energy Balance
- In Fig. below is illustrated energy balance of a standard FPC. From total solar radiation IT incident on glass cover, a part (τ · IT) determined of transmittance τ reaches the absorber plate where it is transformed in heat. The glass cover reflects in space radiation (ρ · IT) and absorbs radiation (α · IT), where ρ and α are the glass cover reflectance and absorptance, respectively. One part of rad…