uk naval ships hvacr maintenance of legacy systemsashrae.gr/eeins2015/eeins2015_steward.pdf ·...

UK Naval Ships HVACR – Maintenance of Legacy Systems

Robin Steward [email protected]

Younus Abbas [email protected]

Babcock International Group Energy and Marine Technology

EEinS2015 - International Conference “ENVIRONMENT & ENERGY in SHIPS 2015”

Objectives

• Operation and maintenance of HVAC

• Standards and legislative framework

• Issue 1. Ventilation fresh air improvements for health of crew

• Issue 2. Upgrading air conditioning on UK Naval Ships: Option 1. Upgrade to whole system

Option 2. Reducing the chilled water supply temperature

Option 3. Efficiency savings using air-to-air recovery

Scope: Ventilation and chilled water system on naval vessels


Outline


– Overview of ship and HVAC – Part1: Fresh air upgrade to ventilation system

• Ventilation overview • Flow rate assessment • Proposed solutions • Summary

– Part2: Air Conditioning Upgrade • Current System Overview • Using standard CW temperatures • Using lower CW temperatures • Using energy recovery units • Summary

– Questions

Ship & HVAC Overview


Ship particulars

• Personnel distribution: 342 crew, 1052 full compliment

• Design conditions: Tropical summer (31 °C DB) to sub-arctic winter (-10 °C DB)

• Chilled water plants capacity: 2.8 MW

• Fresh air supply: 12 m3/s

• Recirculated Air: ~80%

• Exhaust: 3m3/s

Part1: Fresh Air Assessment and Upgrade


Fresh Air Safety Requirements

Legislation - Fresh air 5 – 8 L/s per person

- Oxygen >19.5%, nominally 21%

- Carbon dioxide < 0.5%, nominally 0.03%

Standards - 15 air changes per hour

- CO2 below permitted maximum levels

- At whole ship 13 L/s per person

Constraints:

• Accuracy of Measurements and Balancing

• Changing distribution of personnel


Ventilation System Overview


F.A.

AFU

AHU

HEATER

FILTERED AIR

BATHROOM

AND HEADS

GENERAL

COMPARTMENT

RECIRCULATION FILTER

HEATER

AHU

EF

Fresh Air Make-Up Assessment

Whole Ship:

Personnel requirements (1052) - 13.7 m3/s

Ship supply - 12 m3/s

Example zone:

Zone personnel requirement (331) - 4.3 m3/s

Zone supply - 3.0 m3/s

Example AHU:

AHU personnel requirement (94) - 0.8 m3/s

AHU supply (calculated) - 0.6 m3/s

AHU supply (measured) - 0.5 m3/s

Whole ship exhaust - 3 m3/s


Ventilation Solutions

1.Monitor air quality

2.Upgrade fresh air and exhaust • Example ship +2 m3/s

3.System management • Air flow diagrams

• Software analysis

4.Automation Upgrade • AHU to AFU flow control


Fresh Air and Ventilation Summary

1. Discrepancies between safety guidance and calculated fresh air make-up

2. Key solutions:

• Increase air flow through ship

•Automation of flow between AFU and AHU


Part2: Upgrading Air Conditioning System


Existing HVAC System


M

Evaporator

Condenser Compressor

CW

PUMP

Cooling

Coil Fan

Air

Handling

Unit (AHU)

Thermostat

Exhaust

Solar Radiation

Supply

Air

Recirculated

Air

Fresh Air

from AFU

Re-

Heater

Pre-Heater

Hot Machinery Spaces

Sea Water

S

W

O

CW Plant

E

O

M

W

ADP S

E

31°C db, 27°C wb

29.5°C db, 22.0°C wb

7.5°C db,

14.8°C wb

30.0°C db, 22°C wb

15.0°C db,

13.9°C wb

System Parameters


• Outdoor Conditions – Hot: 31°C db, 27°C wb

– Cold: -10 °C

• Internal Design Conditions – 29.5°C db, 21.5°C wb

• New Outdoor Conditions – 41°C db, 33.4°C wb

O

M

W ADP

S

E

31°C db

27°C wb

29.5°C db, 21.5°C wb

17.5°C db,

14.8°C) wb

N.O

41°C db,

33.4°C wb

Higher Ambient

Temperature

Moore Cooling Capacity

Higher Fresh Air

Temperature

More Heat Conducted

Higher Compartment

Heat Load 30.0°C db,

22.2°C wb

15.0°C db,

13.9°C wb

Upgrading the System Using Standard Chilled Water Temperatures


O

M

ADP S

E

41°C db,

33.4°C wb

32.5°C db

24.4°C wb

17.5°C db,

14.8°C wb

15.0°C db

13.9°C wb W

29.5°C db,

22.0°C wb

• Chilled Water Temperatures Supply : 6.5°C Return: 13.5°C ΔT: 7°C

O

M

W

ADP

S

E

31°C db

27°C wb

29.5°C db

22.0°C wb 17.5°C db

14.8°C wb

15.0°C db,

13.9°C wb

30.0°C db

22.2°C wb

Upgrading the System Using Standard Chilled Water Temperatures


Upgrade AHU (Fan + Coil +

Heater)

Upgrade CW Flow

Rate

Upgrade CW

Piping

Higher Fresh Air

Temperature

Upgrade CW Pump

Higher Heat Load

More Air Flow

Upgrade Ducting

Upgrade Chiller

76.5 kW 87.62 kW

Total Heat

Load

4 m3/s 4.7 m³/s Air Flow

120 kW 184.5 kW Cooling Capacity

4.1 l/min 6.3 l/s

Chilled Water

Flow Rate

18%

54%

54%

15%

Lower Chilled Water Supply Temperature


O

M

AD

P

S

E

41°C db,

33.4°C wb

32.5°C db

24.4°C wb

17.5°C db

14.8°C wb

15.0°C db

13.9°C wb W

29.5°C db,

22.0°C wb

• Chilled Water Temperatures Supply : 4°C Return: 13.5°C ΔT: 9.5°C

O

M

AD

P

S

E

41°C db,

33.4°C wb

33°C db

24.1°C wb

15.0°C db

12.8°C wb

12.5°C db

11.8°C wb W

30.1°C db

19.8°C wb

Lower Chilled Water Supply Temperature


76.5 kW 87.62 kW

Total Heat

Load

4 m3/s 3.75 m3/s Air Flow

120 kW 166.3 kW Cooling Capacity

4.1 l/min 4.1 l/s

Chilled Water

Flow Rate

-6%

39%

0%

15%

Upgrade AHU (Fan +

Coil+Heater)

Upgrade CW Flow

Rate

Upgrade CW

Piping

Higher Fresh Air

Temperature

Upgrade CW Pump

Higher Heat Load

More Air Flow

Upgrade Ducting

Upgrade Chiller

X

X

X X

Lower Air Temperate

Supply

Upgrade Cooling Coil

Capacity

Air-to-Air Energy Recovery


O

M

ADP S

E

32.5°C db

24.4°C wb

15.0°C db

12.8°C wb

12.5°C db

11.8°C wb W

30.1°C db

19.8°C wb

OE 34.0°C db

26.7°C wb

41°C db,

33.4°C wb

Out Door Air 31.0°C db, 27.0°C wb

Compartment Exhaust Air 29.5°C db 21.5°C wb

Out Door Air 41.0°C db, 33.4°C wb

Compartment Exhaust

29.5°C db, 21.5°C wb

Fresh Air Supply 34.0°C db, 26.7°C wb

Exhaust Air 36.6°C db 28.0°C wb

ERV

70%

Sensible

56.7% Total

Cooling Enthalpy -23%

Air Conditioning Upgrade Summary


120 kW 128.3 kW 7%

120 kW 184.5 kW

Cooling Capacity

54%

120 kW 166.3 kW 39%

• Standard CW temperature

– Upgrade all main components

• Lower CW Supply temperature

– Upgrade chiller plant

• Energy recovery units

– Increase in efficiency


Robin Steward [email protected]

Younus Abbas [email protected]

uk naval ships hvacr maintenance of legacy systemsashrae.gr/eeins2015/eeins2015_steward.pdf ·...

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