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AHU Dehumidification 1.0 OVERVIEW The purpose of this document is to provide the base design information in order to calculate the average annual energy consumption figures and provide the information to assess the life cycle cost for three different methods of cooling and dehumidification based on multiple external and internal design conditions. This information will then be provided as a guidance note for GSK sites globally to allow them to assess the most economical solution for maintaining humidity conditions relating to product and or personnel requirements. The three methods of cooling and dehumidification would be assessed as follows:
Cooling coil; for the purposes of these calculations will be a chilled water coil.
Desiccant wheel type dehumidification system
Liquid desiccant type dehumidification system The external design data used for the calculations will be derived using data for varying extremes of external conditions in order to give a good information base for all sites globally. The calculations and equipment selection will be for five Global locations. These locations are as follows:
Tianjin, China
Parma, Italy
London, UK
Nashik, India
St Louis, USA
The internal room design condition will be at a fixed temperature of 21C with varying %RH conditions covering 60%, 50%, 40%, 20% as a set point. In addition the calculations are to include for a variety of fresh air / recirculation air combinations, these being 100% fresh air, 50%, 20% & 10%. Energy consumption results will be provided for every Region, combination of fresh air and relative humidity for each month of the year. Capital, maintenance and other operating costs will be required.
1.1 DOCUMENT OBJECTIVES The document objectives are as follows:
Establish average monthly KWh consumptions for each month of the year for each HVAC solution
Provide Global Guidance for humidity control dependent upon the climate zone and conditions
Provide typical Internal sensible and latent heat loads
Define design conditions for the HVAC system services; chw temp, lphw temps steam pressures
Define options for renewable sources for the desiccant systems. 2.0 DESIGN PARAMETERS & ASSUMPTIONS The systems outlined above have been designed to generally meet with the requirements of the following standards and specifications.
DG3001 HVAC General Design Principals
DG1301 Design for Energy Efficiency
C.I.B.S.E Guides
Chilled water Flow 6oc return 12oc
LPHW Flow 85oc, 65oc Return Steam 3 Barg Steam. Condensate return connections Operational Hours For the calculation the plant will be operational 24/7, 8760 Hrs System Design Conditions A supply temperature of 16oc sensible will be required at all times to offset the internal gains, at the required dew point to maintain the desired room humidity conditions for the product. Product Specific Assumptions
Desiccant Wheel
Steam & Electric reactivation alternatives to be provided
Energy saving equipment to be offered to maximise energy efficiency
Reactivation air Heat recovery utilising Heat pipe or Cross flow heat exchanger to be provided
Liquid Desiccant
Options to be provided for both Primary Utilities and Renewable sources
Options for Hybrid & Heat pump options to be provided
2.1 DESIGN CONDITIONS The following table shows the monthly design wet bulb and the mean coincident dry bulb temperatures to be used as for comparison only in the calculations. These shall be used as average monthly temperatures across the whole month:
Month
Site: Tianjin, China
Site: Parma, Italy
Site: London, UK
Site: Nashik, India
Site: St Louis, USA
Ambient Condition
Ambient Condition
Ambient Condition
Ambient Condition
Ambient Condition
DB
(C) WB
(C) DB
(C) WB
(C) DB
(C) WB
(C) DB
(C) WB
(C) DB
(C) WB
(C)
Jan 6.5 2.2 11.5 9 12.5 11.6 29.1 24.2 16.5 14.5
Feb 10.9 6 17.5 11.7 13 11.6 29.3 23.8 19.8 16.2
Mar 19.1 12 19.5 14.4 15.9 12.5 30.7 26.5 24.6 18.8
Apr 25.4 18.5 22.6 16.7 19.4 14.7 32 27.2 27.2 21
May 30.5 22.5 28.3 21.3 23.5 17.8 32.4 28.2 29.7 24.2
Jun 31 25.5 30.1 24.5 26.6 20 31.9 28.2 32.2 26.3
Jul 33.1 28.5 31.9 26.3 28.3 20.8 30.6 27.7 33.9 27.5
Aug 31.7 27.9 32 25.6 27.6 20.6 30.1 27.4 33.3 27
Sep 29.3 25.8 27.7 23 24.1 19 31.2 27.7 31.7 26
Oct 23.5 19.4 22.5 19.6 20.5 17.2 31.7 27.9 25.6 21.9
Nov 15.9 12.1 15.8 14.2 15.7 14.5 32.3 27 22 18.7
Dec 8.4 4.6 10.8 10.2 13.6 12.7 30.1 24.8 19.7 17
ROOM DIMENSIONS
DG3001 requires that the air conditioning and ventilation systems are designed to provide minimum air change rates within specific areas. For this design study a primary packaging area has been selected with an air change rate of >10ACPH is specified. For the purposes of these calculations an air volume of 3m/sec will be utilised this will give an air change rate 11 air changes per hour for the following room size.
ROOM SIZE
Height of room: 3.0mtrs Room area: 330.27m
HEAT GAINS
Internal Heat Gains For the calculation purposes we have assumed a supply set point of 16
oc and a Sensible Heat Ratio
(SHR) of 0.9 which is fairly typical of a production environment. 3.0 REQUIRED OUTPUTS BY EQUIPMENT SUPPLIERS
1. Energy calculation for each month in Kwh, (electrical & utility consumption) 2. De-humidification plant capital Plant costs including delivery & commissioning costs to each
Global site. (+/- 25%) 3. 5 year maintenance contract costs (+/- 25%) including materials, fluids & labour at site.
EECO2 will provide analysis of cooling water energy consumption across all options and will take responsibility for compiling & assessing results for this analysis.
APPENDIX 1 - SCHEMATIC DRAWINGS
APPENDIX 2 TYPICAL ENERGY CONSUMPTION OUTPUT
TABLES
RESULTS TABLE GSK SITE:
MONTH
HVAC System; 3m/sec 100% fresh air
Room Condition Room Condition Room Condition Room Condition
21C 60% RH 21C 50% RH 21C 40% RH 21C 20% RH
Consumption KWh
Consumption KWh
Consumption KWh
Consumption KWh
Ele
ctr
ica
l
Oil/G
as
Heati
ng
&
Co
olin
g
Ele
ctr
ica
l
Oil/G
as
Heati
ng
&
Co
olin
g
Ele
ctr
ica
l
Oil/G
as
Heati
ng
&
Co
olin
g
Ele
ctr
ica
l
Oil/G
as
Heati
ng
&
Co
olin
g
January
February
March
April
May
June
July
August
September
October
November
December
Note: Tolerances as follows:
Temperature: +/- 2C Humidity: +/- 5%
RESULTS TABLE GSK SITE:
MONTH
HVAC System; 3m/sec 50% fresh air
Room Condition Room Condition Room Condition Room Condition
21C 60% RH 21C 50% RH 21C 40% RH 21C 20% RH
Consumption KWh
Consumption KWh
Consumption KWh
Consumption KWh
Ele
ctr
ica
l
Oil/G
as
Heati
ng
&
Co
olin
g
Ele
ctr
ica
l
Oil/G
as
Heati
ng
&
Co
olin
g
Ele
ctr
ica
l
Oil/G
as
Heati
ng
&
Co
olin
g
Ele
ctr
ica
l
Oil/G
as
Heati
ng
&
Co
olin
g
January
February
March
April
May
June
July
August
September
October
November
December
Note: Tolerances as follows:
Temperature: +/- 2C Humidity: +/- 5%
RESULTS TABLE GSK SITE:
MONTH
HVAC System; 3m/sec 20% fresh air
Room Condition Room Condition Room Condition Room Condition
21C 60% RH 21C 50% RH 21C 40% RH 21C 20% RH
Consumption KWh
Consumption KWh
Consumption KWh
Consumption KWh
Ele
ctr
ica
l
Oil/G
as
Heati
ng
&
Co
olin
g
Ele
ctr
ica
l
Oil/G
as
Heati
ng
&
Co
olin
g
Ele
ctr
ica
l
Oil/G
as
Heati
ng
&
Co
olin
g
Ele
ctr
ica
l
Oil/G
as
Heati
ng
&
Co
olin
g
January
February
March
April
May
June
July
August
September
October
November
December
Note: Tolerances as follows:
Temperature: +/- 2C Humidity: +/- 5%
RESULTS TABLE GSK SITE:
MONTH
HVAC System; 3m/sec 10% fresh air
Room Condition Room Condition Room Condition Room Condition
21C 60% RH 21C 50% RH 21C 40% RH 21C 20% RH
Consumption KWh
Consumption KWh
Consumption KWh
Consumption KWh
Ele
ctr
ica
l
Oil/G
as
Heati
ng
&
Co
olin
g
Ele
ctr
ica
l
Oil/G
as
Heati
ng
&
Co
olin
g
Ele
ctr
ica
l
Oil/G
as
Heati
ng
&
Co
olin
g
Ele
ctr
ica
l
Oil/G
as
Heati
ng
&
Co
olin
g
January
February
March
April
May
June
July
August
September
October
November
December
Note: Tolerances as follows:
Temperature: +/- 2C Humidity: +/- 5%
