Hot Water Solutions for a Changing Climate

8/13/2019 Hot Water Solutions for a Changing Climate

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Solar thermal

And its integration with

commercial and industrial hotwater systems


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Lochinvar Ltd

Steve Addis L.Z.C product manager


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Our company

In the UK since 1976

Relocated to newheadquarters in 1998

Lochinvar corporation startedin 1919

2001 relocated to 360,0002ftfacility

Major player in high

efficiency water heater &boiler industry in USA


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Basic system design

Designing a solar thermal system

System components

Sizing solar systems

Integration with DHW systems


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System components

A solar thermal DHW system requires:

A solar collector

Storage vessel or heat exchanger

Pipe workControl system

Primary heat source


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System components

There are 2 main types of solar collectors

Flat plate

Evacuated tube


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Solar collectors Pros

Flat panel

Simple design

Long warranties

Better at handling

stagnation Cheaper

Can be roof integrated

Better looking?

Evacuated tube

Higher efficiency on lowirradiation days

Smaller surface area?

Lighter?

Repairable


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Solar collectors Cons

Flat panel

Can be Heavier

Larger surface area

required?

Less efficient on lowIrradiation days

Evacuated tube

Seen as delicate

Can need highermaintenance

Will overheat readily ifstagnation occurs


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Solar collectorsLochinvar G1000-10 flat

plate collector


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Solar collectorsLochinvar G1450-10 flat

plate collector


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Solar collectorsLochinvar CPC Evacuated tube

collector


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Solar collectors

Evacuated tube collector principles


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Solar collectors

All solar collectors must be certified to BSEN 12975

Look for the solar key mark

The Key to grants


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Collector efficiency

Collector efficiency consists of:

Absorber efficiency (average 75%)

Minus absorber emissions 2%-14% (dependant

upon insulation and selective coating)This will be shown as A1/A2 heat loss coefficient

Collector efficiency will change according

to

t between collector fluidtemperature and outside air


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Care should be taken to ensure the collectors are sitedcorrectly.

South facing - 30-40 degrees inclination

Avoid shading


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Collector Efficiency

Chart showing the effects of varying the inclination andazimuth of collector field

Inclination

Azimuth

South SE/SW E/W NE/NW N

Horizontal 933

30o 1042 997 886 762 709

45o 1023 968 829 666 621

60o 960 900 753 580 485

Vertical 724 684 565 427 360


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Solar collectors

Roof integration can be difficult on commercial buildings

Architects/structural engineers need to be involved atdesign stage

Need to think about maintenance and possible futurereplacements


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Solar col lectors

Collectors on A frame new building


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Solar col lectors

Collectors on A frame


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Solar col lectors

A frame with ballast prior to collector installation


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Solar col lectors

Collectors on a pitched roof


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Solar col lectors

Collectors on a pitched roof


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Solar col lectors

Collectors on facade


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Solar collectors


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System components

Storage vessel or heat exchanger

Must be sized accurately for collectors

CIBSE guidelines ask for a dedicated solar store of:

50-60ltr/m2

on evacuated tube systems35-50ltr/m2 on flat plate systems

Manufacturers often ask for more

Usually installed next to the primary heat source

Heat exchangers used for specialised applications


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Solar store

Pre-heat store

Direction

of natural

buoyancy


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Solar store Twin-Coil

Direction

of natural

buoyancy


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Controls: legionella

Legionella colonisation could occur within the solar

vessel, especially during spring/autumn when

temperatures within the vessel are likely to be lower.

Temperature controlMechanical control


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Solar Thermal store


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Pipe work (sealed system)

Must be sized to suit the individual project

Should incorporate appropriate safety valves

and expansion vessels/protection vessels

Either specialist solar pipework systems or

Copper with high temperature press-fit fittings


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Solar Control functions

Sollar Array

R1S1 S2


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Solar Control functions solar display panel


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Controls: safety heat-dump arrangement

R1S1 S2 S4 R3


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Primary heat source

The primary heat source will satisfy the majority of the hotwater demand, therefore careful consideration should alsobe given to this part of the design.

Efficiency of primary heat source is important

Considercondensing technology


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Sizing of solar systems

Project CriteriaIn order to provide an accurate sizingthe following information is required:

Daily hot water demand

SOLAR FRACTIONrequired

Post code of the building

Type of building

Number of occupants perday

Roof space available andorientation/pitch of roof


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Tsol sizing: calculation example


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System efficiency

To RecapSystem efficiency is dependant upon:

Type of collectors used

Temperature of the DHW systemInstallation of collectors

Solar fraction

Correct sizing of solar storage vessel

System efficiency is typically around

50%-60%


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System efficiency


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System integration

The main methods of integration are:

Hot water systems

Twin-coil calorifier

Pre-heat storeSwimming pools

Heat exchanger


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Integration with pre-heat solar vessel


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Integration with pre-heat solar vessel and heat

dump


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Solar system with HSK Thermal store and

boiler support

COLD IN

Expansion Vessel

EV

NRV

PRV

Expansion Vessel

EV

Pump

TD

TD

IVIV

Boiler

LSV LSV

NRV

EV

TD

A.S.

D.S.

Boiler

LSV LSV

NRV

EV

TD

D.A.

P.P.

240V

2 PV


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System maintenance

Collectors are generally self cleaning due to angle sited

Pressure within the system checked annually

Circulation pump checked annually

Visual inspection of collector array every 1-2 years

Check glycol mix condition annually


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Thank you for l istening

We would be pleased toanswer any questions?

e-mail: [email protected]

www.lochinvar.ltd.uk

Documents

Hot Water Solutions for a Changing Climate