Heat Recovery & Indoor Pools

• UK manufacturer and market leader

in heat pump technology

• Established 1977

• Supplied more Heat pumps in

UK than any other manufacturer

• Manufactured over 250,000 heat pumps to date

• Based at 80,000 sq ft facility in Maldon Essex

• Export circa 65% of finished goods

Calorex Profile

Calorex

Heat Pumps

Indoor

Swimming Pools

Environmental Climate

Control Systems.

Heat Recovery

&

Dehumidification

Outdoor

Swimming Pools

Air source

heat pumps

Portable

Equipment

Building Dryers

Air Conditioners

Air Movement

Domestic

Heating

Ground & Air source

Heat pumps

Dehumidification

Dehumidifiers

Humidifiers

Heat Recovery

Calorex Product

Applications

Services

• Free Project appraisals - including site visits

• Free sizing advice and product selection

• Commissioning

• Maintenance contracts

• Extended warranty

• Nationwide service network.

• Over 30 service agents covering UK & Ireland

Some detail

• Large Indoor pools

• Public pools & leisure centres

• Energy use

• Running costs

• Dehumidification & ventilation

• Heat recovery

• Case study

South Moorlands

Leisure Centre

Setting the Scene

• Large number of Leisure Centres 20-30 yr old

• Existing AHU’s often use full fresh air

• Energy use in Leisure Centre with pools is high

• Energy costs rising - find ways of reducing running cost

• Associated CO2 emissions

• Environmental impact

• Carbon footprint

• Best practice

Benchmarks - Dry v Wet

Annual Energy

Use (kWh/m2)

Dry Sports Centre

Leisure Pool Centre

Typical Good

Practice

Typical Good

Practice

Electricity 105 64 258 164

Heating Fuel 343 158 1321 573

Ref: ECG078

Benchmarks Leisure Centre with Pools

• Total Area = 2500m2 (pool hall 1090m2)

• Pool Area = 540m2

Leisure Centre

with Pools

Annual Energy Use (kWh/m2)

Typical Good Practice

Electricity 258 164

Heating Fuel 1321 573

Costs £119,250 £59,800

CO2 905 tonne 448 tonne

Energy Use

Leisure Centre with Pool

Energy Use

Leisure Centre with Pool 2 main uses of energy

• Air Heating 42%

– Ventilation and building losses

• Water heating 17%

– evaporation, back wash & dilution

• Potential for 50% reduction in air heating and pool water

energy use

• Potential to reduce energy use of centre by 29.5%

• Reduction in running costs

• Reduction in associated CO2 emissions

Public Pools

Municipal Pools and Leisure Centres

• Large surface area

• High usage

• Long hours

• Additional water features

• Large number of occupants

• Spectators

Fundamental Requirements

for Pool Complexes

• WATER HEATING

Replenish pool water heat losses

• AIR HEATING

Replenish/maintain pool air above pool temperature

• DEHUMIDIFICATION

Remove moisture from pool hall air

• FRESH AIR

Ventilate at minimum acceptable rates

• HEAT RECOVERY

Use available latent heat

Dehumidification

Affects of Uncontrolled Humidity

• Condensation

• Damage to building

• Structural damage

• Damage to fabric, fixtures and fittings

• Mildew and mould growth

• Personal discomfort

What do indoor

swimming pools require?

1. A pool temperature of between 28ºC and 30ºC to make swimming pools suitable for swimmers

2. Pool hall air at 1ºC above pool temperature to minimise evaporation of pool water

to minimise transmission loss to air to provide a comfortable condition for occupants

3. Relative Humidity of 55-65%RH to prevent condensation and damage to building to provide a comfortable condition for occupants

4. Fresh Air Ventilation at 10 litres/sec/person or

3 litres/sec/m2 pool area Dilute CO2 build up reduce airborne chemical build up

Fresh Air Requirements

• Number of guides state ventilation rates based on air

change rates in the pool hall

• Traditionally based on using fresh air for dehumidification • CIBSE Guide B2, section 3.21.7

Overall 4-6 or 8-10 ac/h dependant on use

Fresh Air at 10 l/s/m2 pool hall area & 12 l/s/pers

• SPATA Standard Vol 2, section 3

Fresh Air at 10 l/s/pers & 3 l/s/m2 pool area for dilution of CO2 and

chemicals

• ISRM & ILAM – advice based on air changes

• Any fresh air introduced will need to be heated

• Should be kept to a minimum for occupancy & dilution only

Heat Losses from a Pool

There are three major sources of heat loss

• Evaporation from pool – 65%

• Radiation – 20%

• Conduction into ground – 15%

Note

Use of a pool Cover will significantly reduce the heat losses from a pool and therefore the heat input required

Typical Swimming Pool

Losses

• At 28ºC a pool loses an average of 20 litres/hour

per 100 square metres of pool area

• For a 6 lane 25m standard pool, area 325sqm, this

equates to 65 litres per hour

• The energy content of this moisture is 0.627kWh

per litre

• This equates to 65 x 0.677 = 44kW available to be

recovered

• Recovering this energy will make a significant

contribution to the pool energy usage

Dehumidification Systems

There are several types of dehumidification systems

available:-

• 100% Fresh air

• Fresh air and heat recovery

• Partial re-circulation

• Mechanical dehumidifier

• Heat pump dehumidifier

Some offer heat recovery

100% Full Fresh Air

100% Full Fresh Air

• Simple supply and extract AHU

• No heat recovery

• Large air heater battery to maintain pool hall

temperature

• All moisture and heat exhausted

• Approx 6-8 air changes required to give sufficient

dehumidification at peak ambient dew point

• Many existing pools still using this type

100% Full Fresh Air

Recuperator

• 100% fresh air, no recirculation

• Heat recovery with plate heat exchanger

• 50-60% efficiency

• At what condition?

• Supply air at -5oC and extract air at 30oC

• Possible modulation of air flow volume to suit duty; eg

lower air flow at night

• Also used; run round coils & rotary wheels

Run-around Coils

Rotary Wheel

ss ss

ss

ss ss

ss

ss ss

Recuperator &

Recirculation

Recuperator &

Recirculation

• Recirculation to give fixed air flow volume

• Fresh air volume modulated to suit DH duty

• Minimum fresh air approx 30% of day time duty during

night time operation

• Heat recovery with plate heat exchanger

• Heat recovery to air only

• Up to 75% efficiency claimed for double pass recuperator

• At what condition? Inlet -5oC, extract 30oC?

• Little or no latent heat recovery

Recuperator & Heat Pump

Recuperator & Heat Pump

• Heat pump added after recuperator

• Additional heat recovery

• Some latent heat recovery

• Only used on exhaust air

• No heat recovery on by-pass path

• Heat recovery by-passed in summer

• Can offer option of heat recovery to water

Desiccant Fresh Air

Inlet

Heater

Heater

Pool Hall

Wet Air

Exhaust

Exhaust

Air

Desiccant

• Uses desiccant dehumidifier to do some DH duty

• Fresh air modulated to suit extra duty required

• Fresh air can be reduced to minimum during

unoccupied periods

• No heat recovery to air or water

• Heat gain through rotor only 50% of regeneration heater

energy use

• Pay twice to evaporate water. Once for pool heating &

then for regen heater to evaporate from desiccant rotor

• Life of rotor 7-10 years

Calorex Systems

• Based on heat pump dehumidifiers

• Recovery of Latent heat

• Recovered heat returned to air or water

• Air re-circulated

• Fresh air introduced when required

• Units available for all pool sizes from small domestic

to Olympic sized public pools

• Stand alone units to fully packaged AHUs

Calorex HRD System

What is a Heat Pump?

• A heat pump is a thermodynamic device capable of

recovering energy from one medium, enhancing it and

transferring it to another

• Heat pumps are usually based on a refrigeration cycle

• They are often viewed as a ‘fridge in reverse’

• Unlike refrigerators the primary aim of a heat pump is

to provide heating

A Heat Pump is a

fridge in reverse

Types of Heat Pump

• Usually described on basis of mediums between which heat is transferred

• Air to air

• Air to water

• Water to air

• Water to water

• Geothermal or ground source

Heat Pump Cycle

COP = Coefficient of

Performance

COP = Total Heat Output

Energy Consumed

Why use a Heat Pump?

• Recovered energy

• Energy efficient

• Environmentally friendly

• Lower running costs

• Swimming pool water usually at 28-30oC

• Air temp usually 30oC

• Ideal operating conditions for heat pump

• COP of approx 5

• Efficiency 500%

• Subtract fan energy use, efficiency still 300%

Heat Pump Dehumidifier

Calorex Variheat System

Calorex HRD

Calorex HRD

Calorex HRD

Benefits of HRD

• HRD controls air temp, water temp, humidity and fresh air introduction

• Pool hall air re-circulated

• Fresh air modulated to keep to minimum

• Fresh air volume dependant on air temp, humidity or occupancy

(AQ/CO2) sensor

• Fresh air volume of up to 72% of re-circulated volume

• Energy saving due to latent heat recovery

• Heat recovery to water and air

• Heat recovery to water sufficient to make up all of operational pool

water heat losses

• Save 30-40% of running cost compared to recuperator based system

with variable fresh air

• Significant reduction in associated CO2 emissions

Benefits of HRD

• Compact size

• Fully packaged unit including controls

• Controls can be stand alone or utilise local BMS controller

• Smaller LPHW air heater required due to lower fresh air

volumes

• Boiler capacity required therefore reduced compared to

AHU with recuperator

• Associated project costs lower:- • Boiler

• Controls • Plant room space

HRD Kimbolton School

Advantages of Calorex

• Wide product range

• Comprehensive range of options

• Specifically designed for swimming pools

• Established reputation

• High quality and reliability

• Excellent product support, before & after sale

• Continuous product development

• All units factory tested prior to despatch

Case Study

Typical Local Authority Leisure Centre

• Main Pool; 25m x 13m

• Learner pool; 13m x 8.5M

• Deck level type

• Water in main pool at 28oC and learner pool at 30oC

• Air at 30oC & 60%RH

• Pool hall volume; 5000m3

• Municipal use, high activity, 16 hrs per day

• No pool covers

Willowburn Sports and LC

Sizing of Heat Pump

Dehumidifier Dehumidifiers are sized to cope with the average evaporation

from a pool over a 24 hour period and maintain the correct

humidity, usually 60%RH.

Fresh air is used to assist with humidity loads at times of peak

usage

Factors that influence selection are:- • Pool surface area

• Water temperature

• Air temperature

• Pool hall volume

• Building heat losses and gains

• Pool cover

• Usage

• PoolCalc selection programme

PoolCalc

Equipment Selection:-

Calorex

HRD30

Evaporation

Calorex HRD 30 Data

• Airflow = 9.7m3/s (35,000m3/h)

• Power consumption = 44kW

• Heat recovery = 131kW (mode A; 117kW to water & 14kW to air)

• Efficiency = 297%

• Air heater = 210kW

• Size = 4.15m l x 1.75m w x 2.53m h

Energy Analysis

Energy Usage - kWh

Comparative Energy Use per Annum

0

500000

1000000

1500000

2000000

2500000

3000000

3500000

4000000

Full Fresh Air Desiccant AHU Recuperator

AHU

Heat Pump

HRD30

En

erg

y U

se -

kW

h p

er

an

nu

m

Gas Regen

Heater

Gas water

heating

Gas air heating

only, building

losses not

included

Electricity

compressors &

fans included

Energy Analysis

Running Costs

Running Cost per Annum

Full Fresh Air

£94,746

Desiccant

AHU

£69,334

Recuperator

AHU

£50,407

Heat Pump

HRD30

£31,885

£-

£10,000

£20,000

£30,000

£40,000

£50,000

£60,000

£70,000

£80,000

£90,000

£100,000

Co

st

per

an

nu

m

Elec = 6.2p/kWh

Gas = 2.4p/kWh

Energy Analysis

CO2 Emissions

CO2 Emissions per Annum

Full Fresh Air

1048

Desiccant

AHU

723

Recuperator

AHU

510

Heat P ump

HRD30

229

0

200

400

600

800

1000

1200

To

nn

es

CO

2 p

er

an

nu

m

Leisure Centres

• In Britain there are 1,650 public sites with a total of

2,541 pools (source; Leisure Database Company)

• CO2 saving per site when adopting Heat Pump

technology from 281 to 819 tonnes per annum

• A potential UK wide reduction of between 464,000 and

1,350,000 tonnes CO2 per annum

Health Clubs &

School Pools

• There are a further 1,362 private sites with a total of

1,508 pools (source; Leisure Database Company)

• Assume CO2 saving per site is half that of Leisure

Centre, i.e. from 140 to 410 tonnes per annum

• An additional potential UK wide reduction of between

191,000 and 558,000 tonnes CO2 per annum

Reference Projects - UK

• Cally Pool, Islington – HRD30

• St Helens Pool, Huntingdon – HRD15

• Camberwell Baths – HRD25

• William de Ferrers Centre, Essex – HRD20

• RJ & AH Hospital Hydrotherapy Pool – HRD25

• Queens Drive Recreation Centre, Liverpool – HRD20

• Pontypool Leisure Centre – HRD30

• Royal Wolverhampton School – HRD20

• Over 250 HRD units installed in pools, worldwide

• 10,000s of Calorex heat pump ventilation units operating in

pools of all sizes in UK and overseas

Cally Pool, Islington

Running Costs

£64,469

£42,333

£-

£10,000

£20,000

£30,000

£40,000

£50,000

£60,000

£70,000

Energy Cost

Total 08-09

Total 09-10

Reduction: £22,135 in first 7 months or 34%

Project annual reduction: £38,000

CO2 Reduction

513 tonne

335 tonne

0

100000

200000

300000

400000

500000

600000

Total CO2 Emission kg

Total 08-09

Total 09-10

Reduction: 177 tonne in first 7 months or 35%

Project annual reduction: 305 tonne

Funding

• Enhanced Capital Allowances (ECAs) – ETL categories for heat pump dehumidifiers

• Carbon Trust & Siemens interest free loan scheme – Interest free loan over 4 years – Ltd company only

– Payback based on energy saving achieved

• Salix Finance – Loans and grants for public sector

– Can assist Local Authorities with Carbon and energy saving projects

• Renewable Heat Incentive (RHI) – Summer 2011 – Subsidy based on ‘metered’ renewable heat generated

– <100kW; GSHP 4.3p/kWh for 20 years; ASHP due 2012

Time for a break

Any Questions?