AQUA SYSTEMS - Heronhill Air Conditioning Ltd

HYDRONIC AIR CONDITIONING 

IMI Air Conditioning Ltd 

AQUA SYSTEMS 

The natural solution for total environmental control 

A four pipe system, 

which utilises 

outdoor reverse 

cycle heat pumps. 

A four pipe system 

which utilises outdoor 

chillers and LPHW 

supply. 

A two pipe system, 

utilising outdoor 

reverse cycle heat 

pumps. 

AQUA MULTI is a two 

pipe system, utilising 

outdoor chillers. 

AQUA systems have a unique split coil design within each indoor unit. Each coil is split into two 

hydraulically balanced segments in the ratio of 70:30. 3 step capacity control of 30%, 70% and 

100% can be achieved by using simple, 2-port motorised valves, operated by the zone’s mini 

outstation. Variable fan speed provides further capacity control. 

■ 

Flexible 

■ 

Environmentally friendly 

modular approach 

All refrigerant in factory charged outdoor units. 

■ 

BMS Controllable 

■ 

Heat recovery 

■ 

central controller and mini-out stations 

Energy efficient 

Performance may be enhanced by using an 

‘Aquavent’ air handling unit. 

Scroll compressors and plate heat exchangers.

Four Pipe Fan Coil System 

Intelligent 4-pipe FCU system served by 2 (or more) air to 

water reverse cycle heat pump chillers, suitable for multizone 

simultaneous heating / cooling applications. 

Four Pipe Fan Coil System 

4-pipe FCU system served by conventional air cooled 

chillers and separate boiler system Suitable for multi-zone 

simultaneous heating / cooling applications. 

■ 

70/30 FCU split coil flexibility 

■ 

70/30 FCU split coil flexibility 

■ 

Communicating Trend control system 

■ 

Communicating Trend control system 

■ 

No pipe run/lift limitation 

■ 

No pipe run/lift limitation 

■ 

No limit to number of indoor units 

■ 

No limit to number of indoor units 

■ 

Heat recovery can be integrated into the system 

■ 

Systems 12-500kW, 16 chiller models 

■ 

AQUA 4 sizing software will ensure correct selection 

and orientation of indoor units 

PRIMARY HEAT 

PRIMARY COOL 

OUTDOOR UNIT 

OUTDOOR UNIT 

BOILER 

INDOOR UNIT ZONE 1 

Valve Open 

Valve Closed 


CHILLER 

ALL HEATING 

Only requirements for heating exist in the building and both outdoor 

units provide hot water to all coil sections, as required. 

PRIMARY HEAT 

PRIMARY COOL 

INDOOR UNIT 

ZONE 1 Cooling 

OUTDOOR UNIT 

OUTDOOR UNIT 

INDOOR UNIT 

ZONE 1 Cooling 

Valve Open 

Valve Closed 

INDOOR UNIT 

ZONE 2 Heating 

Valve Open 

Valve Closed 

INDOOR UNIT 

ZONE 2 Heating 

SIMULTANEOUS HEAT AND COOL 

The Primary Heating heat pump is providing hot water and the Primary 

Cooling heat pump is supplying cold water and the respective coil 

sections are activated. Zone requirements, heat pump mode, valve 

actuation and fan speed are all controlled automatically by the integral 

control system. 

PRIMARY HEAT 

OUTDOOR UNIT 

PRIMARY COOL 

OUTDOOR UNIT 

The larger section of the indoor coil section is connected to the chilled water 

and the smaller to the LPHW. 

SIMULTANEOUS HEAT AND COOL 

A cooling requirement exists in Zone 1 and a heating requirement in 

Zone 2. 

The boiler is providing hot water and the chiller is supplying cold water. 

The respective coil sections are activated to cool Zone 1 and to heat 

Zone 2. 

Determination of Zone requirement, valve actuation and fan speed are all 

monitored and controlled automatically by the integral control system. 


ALL COOLING 

Valve Open 

Valve Closed 


Only requirements for cooling exist , both outdoor units provide cold 

water to all coil sections, as required. 

Design conditions: 

Winter heating and pre-heating; Heating flow / return temperatures 80˚C / 65˚C. 

Summer cooling; Cooling flow / return temperatures 4˚C / 9˚C.

Two pipe fan coil system 

Innovative 2-pipe system with FCU’s served by air to water 

reverse cycle heat pumps suitable for large zones with no 

heating / cooling conflict. 

■ 70/30 FCU split coil for variable capacity 

■ Communicating Trend control system 

■ Reverse cycle heat pump/system capacities 12-500kW 

& multiples thereof 

Two pipe fan coil system 

2-pipe system with FCU’s for cooling only. 

■ Individual FCU or group zone control 

■ Single point responsibility 

■ Communicating Trend controls 

■ No limitation on pipe runs/lift 

■ No limitation to the number of indoor units 

HEAT PUMP 

HEAT PUMP 

CHILLER 

CHILLER 

TO FURTHER HEAT PUMPS 

TO FURTHER CHILLERS 

ZONE 1 

2 1 

2 1 

2 1 

2 1 

TO FURTHER UNITS 


ZONE 2 

STAGE 1 HEATING SHOWN 

2 

2 

ZONE 3 

Valve Open 

Valve Closed 

1 

Valve Open 

Valve Closed 

1 

2 1 

2 1 

2 1 

2 1 



All indoor units located within one zone 


ZONE CONTROL - HEATING MODE (All outdoor units 

on heating) 

ZONE CONTROL - COOLING ONLY 

TO FURTHER ZONES 

Stage 1 Zone temperature is >0.2˚C below set-point . Valve 1 would be 

open, utilising the 30% coil segment. 

Stage 2 Zone temperature is >0.6˚C below set-point . Valve 1 would be 

closed and Valve 2 open, utilising the 70% coil segment. 

Stage 3 Zone temperature is >1.0˚C below set-point. Both valves 1 and 2 

would be open, utilising the full coil. 

Stage 4 Zone temperature >1.4˚C below set-point. Both valves 1 and 2 

would be open and fan speed would switch to high. 

Zone 1 Zone temperature is >0.2˚C above set-point. Valve 1 is open, 

utilising the 30% coil segment. 

Zone 2 Zone temperature is >0.6˚C above set-point. Valve 1 is closed but 

Valve 2 is open, utilising the 70% coil segment . 

Zone 3 Zone temperature is >1.0˚C above set-point. Both valves 1 and 2 

are open, utilising the full coil. 

Boost Cooling. Should the zone temperature exceed 1.4˚C above set 

point, both valves will be open and fan will automatically switch 

to high speed. 

ZONE CONTROL - COOLING MODE (All outdoor units 

on cooling) 

In cooling mode, the system operation is identical to that for heating but 

activated for zone temperatures above set point. All outdoor units will be 

operating on cooling.

Indoor Units 

Three types of Indoor Unit are available: Ceiling Cassettes, 

Wall-Mounted and Concealed Ducted Fan Coils. 

Cassettes 

Standard Features 

• 2, 3 or 4 way air discharge 

• Condensate pump (5m lift) with overflow protection 

• Automatic air deflection 

• Mini outstation pre-loaded with relevant AQUA 

strategy 

• High condensate level alarm 

• 70/30 split coil 

• Long life washable filter 

• Fresh air inlet facility 

Optional Accessories 

• Slave cassettes for zones requiring multiple units 

• Branch duct spigots for ducting conditioned air to 

another area 

• Fresh air spigots 

Wall-Mounted 


• Tangential 2 speed fan 


strategy 

• Top or front discharge 

• Adjustable air louvres 


• Long life washable filter 


• Slave Fan-Coils for zones requiring multiple units 

• Condensate pumps (5m lift) with overflow protection 

Concealed Ducted 


• Integral discharge plenum 

• Cleanable filters 


strategy 

• Centrifugal fans with 2 speed selections 

• Left or right hand coil connections (except AQD 70) 



• Slave units for zones requiring multiple units 

• Condensate pump (5m lift) with overflow protection 

• Fresh air connection 

• Return air plenum 

• A choice of spigots for either 200mm or 250mm ducting

AQUA 4 and AQUA 2 reverse cycle heat pumps* 

AQO models; 12, 16, 20, 25, 30, 35, 45, 90 

Nominal cooling capacities from 11- 81kW 

Heating duties from 9.5 - 74kW 


• Wrap around coils 

• Top discharge 

• Plate heat exchangers • Scroll compressors 

• Multi blade axial fans • Auto hot gas defrost 

• Factory fitted isolator 

• Pressure operated fan speed control 

• Mini outstation pre-loaded with relevant AQUA strategy 

AQUA 2+ and AQUA MULTI air cooled chillers* 

AQL models; 50, 70 

Nominal cooling capacities 49.7 and 73.5kW 


• Aluminium casing 

• Scroll compressors 

• Axial fans with head pressure control 

• Trend outstation pre-loaded with strategy 

AQL models; 100, 130, 160 

Nominal cooling capacities from 103.3 - 152.9kW 


• Casing from galvanised steel, powder coated and stoved 

• Scroll compressors 



AQL models; 175, 200, 250, 300, 360, 400, 500 

Nominal cooling capacities from 179 - 477kW 


• Casing from galvanised steel, powder coated and stoved 

• Semihermetic compressors 



Options 

•Full hydraulic package •Low noise versions •R407C 

For full design specifications please contact the Sales Applications Department. 

AQUA SYSTEMS CONTROL FEATURES 

The control system which comes as standard comprises; a central controller with an on-board modem and mini outstations 

within the indoor and outdoor equipment (monitoring supervision via the modem link is optional). Close temperature 

control is provided by four stages of output from every indoor unit, assuring optimum control and minimising temperature 

over-shoot from set-point. 

• Pre-loaded strategy 

• Seven day and holiday programmable timer with night-time setback and three daily time zones 

• Automatic staging of outdoor capacity to match indoor load 

• Optimised start and frost protection 

• Local adjustment of zone set-point temperature (optional)

, 

PERFORMANCE DATA INDOOR UNITS 

CASSETTES 

AQC 620 AQC 640 AQC 40 AQC 50 AQC 60 AQC 80 

Mode Fan PRIMARY COIL 

Total Low 1.36 2.47 2.36 2.60 3.70 5.06 

Cooling High 1.47 2.61 2.57 2.84 3.96 5.54 

Sensible Low 1.36 2.04 1.94 2.14 3.15 3.94 

Cooling High 1.47 2.28 2.29 2.53 3.64 4.58 

Heating Low 1.38 2.03 2.26 2.51 3.69 4.63 

High 1.51 2.25 2.66 2.97 4.26 5.45 

Flow Rate l/s 0.06 0.10 0.10 0.08 0.15 0.18 

SECONDARY COIL 

Total Low 0.67 1.43 1.16 1.62 2.11 2.22 

Cooling High 0.73 1.53 1.28 1.87 2.35 2.44 

Sensible Low 0.67 1.43 0.89 1.15 1.58 1.71 

Cooling High 0.73 1.53 1.05 1.37 1.84 1.99 

Heating Low 0.81 1.52 1.05 1.26 1.83 1.99 

High 0.88 1.66 1.24 1.55 2.18 2.35 

Flow Rate l/s 0.11 0.045 0.05 0.11 0.12 0.10 

BOTH COILS (ie TOTAL CAPACITY) 

Total Low 2.03 3.90 3.52 4.22 5.81 7.28 

Cooling High 2.20 4.14 3.85 4.71 6.31 7.98 

Sensible Low 2.03 3.47 2.83 3.29 4.73 5.65 

Cooling High 2.20 3.81 3.34 3.90 5.48 6.57 

Heating Low 2.18 3.55 3.31 3.77 5.52 6.62 

High 2.40 3.91 3.90 4.52 6.44 7.80 

SOUND PRESSURE LEVELS @3.2m distance in anechoic conditions 

NC Low 31 31 23 22 27 28 

High 34 33 30 29 35 35 

dBA Low 37 38 30 30 34 35 

High 40 39 37 36 41 41 

CONCEALED DUCTED 

AQD 35 AQD 50 AQD 70 AQD 110 AQD 200 


Total Low 1.96 2.98 4.11 6.93 13.83 

Cooling High 2.10 3.30 4.65 7.65 14.42 

Sensible Low 1.57 2.21 3.08 5.20 10.49 

Cooling High 1.79 2.56 3.70 6.05 11.16 

Heating Low 1.87 2.55 3.42 6.10 12.33 

High 2.14 3.01 4.18 7.26 13.24 

Flow Rate l/s 0.09 0.15 0.19 0.27 0.66 


Total Low 1.27 1.65 2.11 3.40 6.92 

Cooling High 1.42 1.87 2.40 3.99 7.17 

Sensible Low 0.92 1.18 1.56 2.33 5.25 

Cooling High 1.06 1.38 1.88 2.80 5.54 

Heating Low 1.04 1.32 1.78 2.37 6.17 

High 1.22 1.59 2.22 2.87 6.56 

Flow Rate l/s 0.14 0.12 0.10 0.16 0.33 

BOTH COILS (ie TOTAL CAPACITY) 

Total Low 3.23 4.63 6.22 10.33 20.75 

Cooling High 3.52 5.17 7.05 11.64 21.57 

Sensible Low 2.49 3.39 4.64 7.53 15.74 

Cooling High 2.85 3.94 5.58 8.85 16.70 

Heating Low 2.91 3.86 5.20 8.74 18.50 

High 3.36 4.60 6.40 10.13 19.80 

SOUND PRESSURE LEVELS* 

NC 32 33 37 33 T.B.A. 

dBA 42 44 44 46 T.B.A. 

*Measurements taken @3.2m distance in a typical hotel bedroom at low fan speed. 

All indoor unit capacities are in kW and for a 20% by weight glycol solution at designated flow rate. 

Cooling conditions Air on23˚C dry bulb, 50% rh 

Glycol on 

4˚C 

Power requirements 220-240V, 1 Ph, 50 Hz (5A) 

Heating conditions Air on 

Glycol on 

21˚C 

40˚C 

WALL-MOUNTED 

AQW 20 AQW 40 AQW 60 


Total Low 0.93 1.99 3.41 

Cooling High 1.10 2.16 3.70 

Sensible Low 0.66 1.59 2.67 

Cooling High 0.81 1.85 3.05 

Heating Low 0.73 1.88 3.14 

High 0.92 2.17 3.62 

Flow Rate l/s 0.13 1.10 0.15 


Total Low 0.45 1.21 1.79 

Cooling High 0.55 1.37 1.99 

Sensible Low 0.30 0.85 1.30 

Cooling High 0.39 0.99 1.49 

Heating Low 0.32 0.95 1.47 

High 0.43 1.12 1.72 

Flow Rate l/s 0.19 0.15 0.13 

BOTH COILS 

(ieTOTAL CAPACITY) 

Total Low 1.38 3.20 5.20 

Cooling High 1.65 3.53 5.69 

Sensible Low 0.96 2.44 3.97 

Cooling High 1.20 2.84 4.54 

Heating Low 1.05 2.81 4.61 

High 1.35 3.29 5.34 

SOUND PRESSURE LEVELS** 

NC Low 25 26 21 

High 28 31 28 

dBA Low 30 32 27 

High 34 36 34 

**@3m distance in anechoic conditions. 

For dimensions contact Sales Applications Department. 

AQUA 2+ cooling coil duties as AQUA 4 (2) 

primary coil figures. 

AQUA 2+ Heating coil duties (kW); 

Low 

High 

Cassettes 2.55 10.22 

Ducted 5.26 34.76 

Wall 2.14 8.2 

Conditions; Heating flow / return temperatures 80 0 C / 65 0 C 

Heating coil flow rate l/s as secondary coil 

AQUA 4 (2) 

AQUA MULTI cooling coil duties as AQUA 4 (2) 

for primary coil, secondary coil and 

both coils (i.e. total capacity). 

All indoor unit capacities are in kW and for a 20% by weight glycol solution at 

designated flow rate. 

Cooling conditions Air on23˚C dry bulb, 50% rh 

Glycol on 

4˚C 

Power requirements 220-240V, 1 Ph, 50 Hz (5A) 



Armytage Road, Brighouse 

W est Yorkshire H D 6 1 QF,England 

Tel: +44 (0)1484 405600 

Fax: +44 (0)1484 721949 

w w w.imi-airconditioning.co.uk 

A subsidiary company of IMI plc 

T B A 

Products comply fully with stringent 

HM British Government Specification 

SEG 136/1. 

IMI Air Conditioning products are 

designed and manufactured in the UK 

and are suitable for a range of ambient 

conditions. For full design information, 

reference should be made to the 

relevant technical manual. Our policy 

is one of continuous improvement and 

we reserve the right to alter designs 

and specifications at any time without 

notification. 

06617543-CD 

Approved to 

B S EN ISO 9001 

Certificate No. FM 671

AQUA SYSTEMS - Heronhill Air Conditioning Ltd

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