Collector Sizing, collector size, Solar Water Heater, Solar Collector

Collector Sizing, collector size, Solar Water Heater, Solar Collector - JinYi FAQ

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Solar collector

1. Heat pipe solar collector

2. U type series

3. Non-pressure series

4. Flat plate solar collector

Non-Pressure Series

1. Aluminium alloy

2. Galvanized steel plate

3. Stainless steel plate

4. Two Pipes Inlet-Outlet

Pressure Series solar

1. Pressurized solar water

2. Pre-heated solar heater

Split Solar Water heating

1. No coils

2. With one coils

3. with two coils

Flat split solar heating

1. Pressurized solar water

2. Non-Pressure solar heater

vacuum tube

1. Normal vacuum tube

2. Three-target tube

3. Heat-pipe vacuum tube

Accessories

1. Pressurized Water Tank

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Collector Sizing

Check out our Frequently Asked Questions in these other JinYi Solar Hot Water Topics:

SOLAR COLLECTOR FAQ	Solar Water heating System Basics Design FAQ
Domestic Hot Water FAQ	Solar Radiant Heating FAQ
Solar pool & Spa Heaters FAQ	installation & solar sizing FAQ
Frequently Asked Questions	Collector Sizing
Insolation level	Energy calculator
Reduces CO2 Emissions

When determining what collector size you need, you must consider two key factors: insolation level and energy requirements. Energy requirement will usually take into consideration the volume of water and rise in temperature required. Once you know these factors you can determine the size collector you require. The bigger the collector you have, the more hot water, but you should make an economically sound decision. Generally it is wise to select a size which will provide you with 90% of your hot water needs in the summer.

Although it may seem strange to use a value of only 90% for summer solar contribution, it is for good reason. It is normal to size based on 100% of your summer hot water energy needs, with a percentage provided throughout other months, lowest obviously in winter. That is based on normal water usage, but often, and particularly in the summer, water usage patterns may not be that normal, with cooler than normal showers taken in hot weather, and greater possibility of the house being vacant for one or two days each week (weekends). As such, using a target value of 90% will probably actually result in a system that is able to supply more than 100% of your hot water needs in the summer, without excessive heat production, which can lead to water loss via pressure release and a waste of energy.

The calculator below can help to determine how many vacuum tubes you require given your energy requirements. Solar collectors come in a set of standard sizing of 12, 15, 18, 20, 24 or 30, depending on your region. Of course you can also combine collectors to increase the size. If you get an answer that is not a standard size, as a general rule, select the next size down - this will prevent having too much heat in the summer.

Depending on your preference, either Metric or Imperial values may be used to calculate the number of tubes required. Please note: 1 kWh/m²/day = 317.1 Btu/ft²/day

Metric Calculation

Insolation:	kWh/m²/day
Water Volume:*	Litres
Temp Rise:**	^oC

You Require:
Vacuum Tubes

Imperial Calculation

Insolation:	Btu/ft²/day
Water Volume:*	US Gallons
Temp Rise: **	^oF

You Require:
Vacuum Tubes

                          *Water Volume = This should represent the actual volume 
                          of hot water used at the tap in total each day. 

                          Although most hot water systems have target temps of 60oC 
                          / 140oF, when showering a 
                          temperature of between 42oC 
                          / 107oF and 45oC 
                          / 113oF is normally used. 
                          Therefore 300L of hot water at the tap may only draw 220L 
                          of hot water (at 60oC / 140oF) 
                          from the storage tank. 

**Temperature Rise = target tap hot water temp - average mains cold water temp.
Target hot water temp should usually be around 42^oC / 107^oF to 45^oC / 113^oF
Cold water usually fluctuates by about 10^oC / 50 ^oF between winter and summer. A check of your local weather records should provide you with an idea of average cold water temperatures (normall about 10^oC / 50^oF in winter and 20^oC / 68^oF in summer, in mild regions).