William Comerford
Sales Manager Ireland
Kingspan Renewables Ltd.
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Energy independent buildings for a sustainable future

Kingspan
Renewables
Division
Kingspan Solar Kingspan HWS
Kingspan Heat
Pumps
Kingspan Climate

What is Solar Energy
Solar energy is radiant energy produced by the sun from a process called nuclear fusion
The energy from the sun acting on the earth’s surface, over a 15 minute period, is more then the earth’s total energy requirement for a year. The amount of yearly global radiation on a horizontal surface may reach over 2,200 kWh/m2 in sunny regions.
In Northern Europe, the values are
943kWh/m2 in London and 990 kWh/m2 in Rosslare, Ireland.
The supply of solar radiation in UK and
Ireland differs by a factor of 10 between summer and winter, e.g. Rosslare: 6.36 kWh/m2/day in June; 0.64 kWh/m2/day in
December

What is Solar Energy
Global radiation comprises direct and diffuse radiation.
As sunlight passes through the atmosphere, some of it is absorbed, reflected and scattered by air molecules, clouds and dust particles, this is known as diffuse radiation.
The portion of radiation that hits the earth’s surface without any change in direction is known as direct radiation.
In Ireland and UK, diffused radiation makes up between 40%
(May) to 80% (December) of the total solar energy available in a year.

Why Use Solar Energy?
Solar energy enjoys many environmental and economic advantages over other forms of energy currently used.
These include:
Environmentally Friendly
•Non-polluting: Solar hot water generation produces no emissions
• Non-consumptive: The suns radiation is a limitless
resource
• Going ‘Green’ for commercial projects has now become a PR advantage
Economically Beneficial
•Cost effective: Free energy source
•Immediate and permanent savings
•Technological advancements: Improvement in solar
technologies offer reduced costs and greater efficiency
The amount of Co2 emissions produced to generate the equivalent of 1,836 kWh: Solar
– 0, Natural Gas:180g/kWh, Oil: 238g/kWh, Electricity 459g/kWh

Why Use Solar Energy?

What Factors Effect a Solar Thermal
System?
Orientation (azimuth) The difference between a collector facing south and a collector facing west = circa 20%, a collector facing north produces
50%
Slope (Inclination)
Collector Area less energy
A collector mounted at 90º will collect 20% less energy then a collector at an angle of 35º
The larger the area the more solar energy available to be
Storage Volume
DHW Demand collected. Care should be taken not to oversize the system
The larger the cylinder volume, the larger the thermal store
The larger the demand the higher the solar energy consumption

What Factors Effect A Solar Thermal System?
• Is solar a viable energy source in UK and Ireland?
• YES!
• Ireland’s daily solar irradiation is circa 3 kWh/m2
• Equivalent to approx 130 litres of oil per m2 per year
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2
3
Zone Average solar radiation on collector surface (kWh/
M²day
2.4 to 3.4
3.4 to 4.4
4.4 to 5.4

The Hard Facts
Domestic Hot Water (DHW) = Approx 21% of our Domestic Energy Consumption
As building standards improve and space heating demands reduce, DHW demand will not change

Collector Types
There are 2 main types of solar collectors
• Flat Plate (Left)
• Vacuum Tube (Right)

Collector Types - Flat Panel Collectors
Riser
System
Serpentine
System

Collector Types - Flat Panel Collectors
• What is the effect of cold weather, wind and rain on a Flat Panel Collector?
Hot
Surface
Cold
Surface
Cold Weather, Wind &
Rain has an ADVERSE effect on performance on a Flat
Plate collector
Gas
Conduction
&
Convection
Losses
Significant
Thermal
Losses to
The
Environment

Collector Types – Evacuated Tube Collectors

Collector Types – Evacuated Tube Collectors
Hot Surface Cold Surface
Cold Weather,
Wind & Rain
DOES NOT effect performance on a vacuum tube collector
Radiation Losses
Minimal Thermal
Losses to The
Environment via
Thermal Losses :
Evacuated Tube
Collector: Pressure < 1 x
10 -6 mbar To
Provide Thermal
Insulation
best insulator available
- Minimises Thermal Losses

Collector Types – Advantages/Disadvantages
Vacuum Tubes
Advantages
• Higher solar yield than flat plate collectors with the same absorber area.
• 30% more effective
• Little thermal loss (only through some radiation)
• As the tube is sealed, dirt or moisture cannot get into the collector
• Works in cold, windy and humid conditions
• Individual tubes can be rotated to optimise ideal orientation
• High temperatures can be achieved
• Some people like the aesthetics of tubes
Disadvantages
• Cost !
• Not easily integrated into the fabric of the building (e.g. roof or facade integrated)
• Some people do not like the aesthetics of the tubes

Collector Types – Advantages/Disadvantages
Flat Plates
Advantages
• Lower cost
• Can be more easily integrated with the fabric of the building (roof integrated / facade integrated)
Disadvantages
• Lower performance through conduction, convection and radiation therefore you need more surface area of collector
• Higher wind load requirements (they act like a sail and catch the wind)
• Glass and absorber can get dirty and effect performance
• Needs more maintenance
• Higher volume content equated to larger component sizes. i.e. expansion vessel
• Isn't as efficient in lower light

Most applications operate at tm-ta = 50degC

Basic Tube Design

Vacuum Tubes – Durability
Always look for the Hail Impact Test Report EN12975
The test is to fire a 25mm ice ball at 50mph at the tubes to ensure durability

2m2 Evacuated Tube System

2m2 Flat Plate Panel System

Stagnation
The occurrence of stagnation in a solar system should be avoided.
Continuous temperatures in excess of 170°C will cause the degrading of the Tyfocor solar solution and degrade its inhibitor properties, this is evident by the solution turning a brown colour (see solution on left in picture below).
The solution on the right is the delivered state of the Tyfocor solution, the beaker on the left contains a solution that has been in stagnation for long periods above 170°C.
The solution should be tested annually using a refractometer and ph test paper.
Stagnation in a solar system can be caused by a number of reasons such as:
• Oversized systems – correct sizing methods have been addressed in previous chapters
• Undersized expansion vessel – correct sizing methods have been addressed in previous chapters
• Air locks or leaks in the system
• Prolonged periods of low hot water demand.

Commercial Solar Applications

One of the best applications for solar thermal due to low demand temps.
High solar fractions achievable on pools in Ireland circa 65-70%

Large System Solutions

Process Applications

System Solutions – Tourism & Agriculture

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