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The leaders in environmental control systems for indoor pools. Available as a CPD - Continuous Professional Development for CIBSE & Mechanical Engineers.
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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?