TRIGENERATION STUDY
Mike Glanfield EPSILON CONSULTANTS (IOM) LIMITED
NOBLES HOSPITAL TRIGENERATION REPORT Report ref: ECL 1244 Dated: July 2014
AUTHOR MICHAEL GLANFIELD MIET Epsilon Consultants (IOM) Limited Registered address: 7 Heather lane Abbeyfields Douglas Isle of Man IM2 7EF Tel: Mobile: Email: Web:
01624 677278 07624 346826 info@epsiloniom.com www.epsiloniom.com
Site address: Nobles Hospital The Strang Braddan Isle of Man IM1 4TE
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July 2014
CONTENTS 1.0
INTRODUCTION
2.0
EXECUTIVE SUMMARY
3.0
BASIS OF CLIENT BRIEF
4.0
DESCRIPTION OF EXISTING INSTALLATION 4.1
Heating Systems
4.2
Cooling Systems
4.3
CHP Installation
5.0
ANALYSIS AND DISCUSSION 5.1
Existing CHP Performance (MSB1)
5.2
Electrical Consumption Data (MSB1)
6.0
ADDITIONAL CHP INSTALLATION (MSB2) 6.1
Additional CHP Estimated Savings (single rate tariff)
6.2
Additional CHP Simple Payback (single rate tariff)
6.3
Additional CHP Estimated Savings (off peak tariff)
6.4
Additional CHP Simple Payback (off peak tariff)
7.0
ADDITIONAL COOLING CAPACITY 7.1
Gas Consumption Data
7.2
CHP Waste Heat vs Cooling Capacity
7.3
Adsorption or Absorption Chiller
7.4
Simple Payback Period
7.5
Option ‘A’ Adsorption Chiller Payback (single rate tariff)
7.5.1
Option ‘A1’ Adsorption Chiller Payback (off peak tariff)
7.6
Option ‘B’ Absorption Chiller Payback (single rate tariff)
7.6.1
Option ‘B1’ Absorption Chiller Payback (off peak tariff)
8.0
WATER COOLING
9.0
NEW PLANTROOM LOCATION
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APPENDICES
I.
EXISTING CHP INSTALLATION – SHOWING FLOWRATE AND TEMPERATURE MONITORING POINTS.
II. III.
DIMENSIONS & WEIGHT SCHEDULE.
IV.
ABSORPTION CHILLER - REFERENCE SPECIFICATIONS.
V.
ADSORPTION CHILLER – REFERENCE SPECIFICATIONS.
VI. VII. VIII.
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THERMAL CHILLER COMPARISON TABLE.
ABSORPTION CHILLER – NOISE DATA. NEW PLANTROOM LOCATION DRAWING. NEW PLANTROOM LAYOUT DRAWING.
July 2014
1.0
INTRODUCTION Epsilon Consultants were appointed to investigate and report on the following: a. The potential for upgrading the existing co-generation CHP (combined heat and power) plant to achieve tri-generation capability. b. The feasibility of providing an additional CHP to meet the electrical demands of MDB2. Reports ref: ECL1204, ECL1235 and ECL1241 should be read in conjunction with this supplementary report.
2.0
3.0
EXECUTIVE SUMMARY a.
The existing CHP system is playing an important role in providing a low energy solution to meet the needs of the Hospital.
b.
An additional CHP gas engine dedicated to meeting the electrical demands of MDB2 would further reduce the costs of purchasing electricity and gas for Nobles Hospital.
c.
Waste heat liberated by the additional CHP engine may be harnessed to assist with meeting the Hospital heating demands and also contribute to meeting the heat load of the thermal chiller.
d.
The cooling capacity of the Hospital may be increased by the introduction of a thermal chiller with the input heat energy being derived from the existing and additional CHPs.
e.
However, the summary table shows a nett shortfall of CHP heat to meet the total heating demands of the hospital and the heat load of the thermal chiller.
f.
The shortfall in CHP heat capacity shall be able to be met by the Hospital steam boilers but the shortfall is likely to increase when the hospital heating demands grow i.e. in the Winter, Spring & Autumn periods.
g.
A nett saving in energy only appears possible by selecting an absorption chiller design, the reason for this is that an absorption chiller is significantly more efficient than an adsorption chiller.
h.
Both thermal chiller designs require cooling to be provided. This may take the form of a cooling tower (forced draft or induced draft) or a dry cooler similar to the existing CHP heat dump.
BASIS OF CLIENT BRIEF The remit given to Epsilon Consultants ltd is to prepare a supplementary report as follows:a. Compare the respective benefits of the different designs of thermal chillers that meet the design requirements. b. Indicate the proposed location of the new chiller, water cooler and CHP installation on a site plan.
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4.0
DESCRIPTION OF EXISTING INSTALLATIONS The main plant area is located in the Energy Centre to the rear of the East wing and accommodates all the necessary plant and equipment required to provide all the services needs of the hospital. 4.1
Heating Systems
The heating plant consists of three dual fuel gas fired (Natural Gas)/oil fired Wellman Robey steam boilers, these are configured as follows;
Description Boiler 1 Boiler 2 Boiler 3 Total
Duty (MW) 2.8 2.8 1.8 7.4
Duty (kw) 2,800 2,800 1,800 7,400
Dependant on the fluctuations of the utilities at the time the heating plant can be switched between fuels to obtain the best value for money available at a given time. Generally the heating load is distributed around the hospital via three heat stations at high temperature. These heat stations then distribute heating for both thermal comfort and domestic hot water from secondary heat exchangers to ceiling mounted radiant heating panels, air handling unit heating coils and domestic hot water systems. 4.2
Cooling Systems
The existing cooling system consists of two roof mounted mechanical chillers, these are located on the flat roof area above the kitchen (CFPU) block. The chillers are manufactured by ‘Powermaster’ model FE/STRAT/LN 1603 and are rated at 423Kw each, giving a total cooling capacity of 846Kw. During construction structural provision was made for the installation of a third chiller unit. The chillers are charged electrically from a 3 phase power supply and provides chilled water to two ice storage vessels located in the energy centre, each vessel is 43 m³ in volume giving a total storage volume of 86 m³. The secondary chilled water is designed to achieve a flow and return temperature of 6°c and 12°c respectively. The chilled water circuit from the ice storage vessels serve a primary plate heat exchanger, which in turn serves the hospital buildings. This heat exchanger is manufactured by Alfa Laval and is rated at 1603Kw
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4.3
Existing CHP installation
The existing CHP Unit is a ‘Guascor’ model SFGLD480 of Indian origin and is a natural gas turbo charged generator rated at 1000 KVA1 (Alternator), as per the manufacturers technical information below: Product Specifications for Natural Gas Guascor Gensets Electrical KW
KVA at 0.8 p.f.
812
1015
Rated Amperes at 415V.0.8 p.f. 1421
Alternator Rating in KVA
Mechanical Brake KW
Engine Model
Useable heat KW
Bore mm
Stroke mm
Cylinder Volume Ltrs.
Weight Kg
1000
838
SFGLD 480
919
152
165
48
8450
The CHP unit was installed around June 2007 by Manx Gas; it is housed in a self-contained block work room within the Energy Centre. The associated heat rejection units are located externally at high level above the main service access doors to the Energy Centre and are interconnected to the CHP unit to enable heat rejection. The heat rejection unit is configured with six fans designed to cool the heating coil, it is manufactured by Heating & Cooling Coils Ltd and has an 80mm flow and return linked directly to the CHP. 5.0
ANALYSIS OF HISTORICAL DATA AND CHP PERFORMANCE 5.1
Existing CHP Performance
The bar chart (figure 5.1) shows the calculated monthly electricity cost savings for the period Dec 2012 – Oct 2013. The dark blue columns shows the savings in kwh generated units and the light blue columns takes into account other MEA charges.
CHP ELECTRICITY COST SAVINGS OCT 2012 - SEPT 2013 £25,000.00 CHP SAVINGS KWH ONLY
£1,978
£6,010
£4,322
£8,768 £3,903
£3,705
£1,773
£8,189
£9,393
£11,158
Dec-12
£6,422
£9,695
Nov-12
£5,845
£9,558
£5,000.00
£10,408
£8,890
£10,545
£10,000.00
£11,104
£13,381
£15,000.00
£15,711
£16,474
£19,489
£20,591
£20,000.00
£22,113
CHP SAVINGS INC OTHER CHARGES
£0.00 Oct-12
Jan-13
Feb-13
Mar-13
Apr-13
May-13
Jun-13
Jul-13
Aug-13
Sep-13
Figure 5.1
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5.2
Electrical Consumption Data (MSB1)
The bar chart (figure 5.2) illustrates the monthly electrical demands for MSB1 for the period Dec 2012 – Oct 2013. The light blue bars on the chart represent the electrical demand of MSB1 to which there is an existing CHP presently connected. The light blue line represents the electrical contribution made by the CHP and varies between 57 – 80% of the total electrical demand. The additional electrical demands (108kva) for the new Hospital works have been obtained from the M&E consultants and are represented by the dark blue bars on the chart.
1,200
ADDITIONAL ELECTRICAL MD: 1) KEYLL DARREE EXTENSION (F) 20.0KVA 2) NICU EXTENSION (E) 45.5KVA 3) ENDOSCOPY UNIT (C) 27.0KVA 4) BREAST CLINIC (D) 15.0KVA
MONTHLY ELECTRICAL DEMANDS MSB1 DEC 2012 - OCT 2013
108
108
108
1,001
1013
1009
582
569
Aug-13
Sep-13
RATED OUTPUT OF CHP (812KW) 108
600
MONTHLY DEMANDS (MSB1) CHP OUTPUT
1,000
800
ADDITIONAL ELECTRICAL MD
857
108
108
867
847
668
678
108
848
657
108
108
854
835
108
1025
108
816
691
685 635
623
599
524 400
200
0 Dec-12
Jan-13
Feb-13
Mar-13
Apr-13
May-13
Jun-13
Jul-13
Oct-13
Figure 5.2
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6.0
ADDITIONAL CHP INSTALLATION (MSB2) The light blue bars on the chart (figure 6.0) represent the electrical demand of MSB2 to which there is no CHP connected at present. The additional electrical demands (102kva) for the new Hospital works have been obtained from the M&E consultants (Hoarelea) and are represented by the dark blue bars on the chart.
Figure 6.0
MSB2 Existing (baseload) Proposed (new load) TOTAL BASELOAD
111 kVA 102 kVA 213kVA Table 6.0
From the information shown above it is possible to make a selection of a suitable rating machine based upon the estimated baseload electrical demands of electrical switchboard ‘MSB2’. Details of a 230kw (e) natural gas powered machine and estimated costs have been obtained from ENER-G Combined Power Limited and included elsewhere in this report. The location for the additional CHP is proposed to be outside of the Energy Centre and housed within a bespoke solidly built structure that could also accommodate the new chiller, water cooler and ancillary equipment. The additional CHP hot water primary circuit shall interface with the existing Hospital LTHW distribution system via a new heat exchanger located in the existing CHP plantroom. The existing CHP secondary pump and controls shall require to be upgraded to accommodate the additional CHP installation. Page |8
July 2014
The suppliers’ budget capital cost for a 230kw e CHP include for the following items only:
ENER-G 230 genset; Low noise heat rejection radiator rated to 65dBA @ 1m; Air fuel ratio controller and catalyst for low NOx emissions; Low noise silencers; Power modulation panel; DRV and 3 port valve for lower than 90°C flow and 80°C return; Gas and heat meters; G59/2 application fee; Supply, delivery and commissioning only.
6.1 Additional CHP Estimated Savings (single rate electricity tariff) The estimated savings summary has been prepared by ENER-G Combined Power Ltd using the following present day energy costs and CHP performance values: PARAMETER MEA single rate ‘industrial tariff’ Cost of natural gas Electricity utilisation LTHW utilisation Availability hours (per annum)
PARAMETER
Capital Electricity Savings LTHW Savings CHP Gas Cost GROSS ENERGY SAVINGS Maintenance NET ENERGY SAVINGS Electricity CO2 Abatement (tCO2) LTHW CO2 Abatement (tCO2) Fuel CO2 Released (tCO2) Total CO2 Abatement (tCO2)
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RESULT 13.42 p/kwh 3.485 p/kwh 100% 40% 90%
RESULT
£ £230,228 £56,501 (£197,219) £89,509 (£25,000) £64,509 823.6 297.8 (1,039.3) 82.1
July 2014
6.2 Additional CHP Simple Payback Calculation (single rate electricity tariff) Additional CHP (MSB2) Supply & delivery (ENER-G Combined Power Ltd) Adaptations to existing CHP installation Installation & Commissioning Ancillaries (controls, BMS interface etc) Total estimated cost * Budget estimate **excludes M&E design fees
£210,000* £50,000* £100,000* £10,000* £370,000**
Simple payback calculation Total estimated capital cost £370,000 Annual estimated energy savings £64,509 Simple payback period 5.7 years 6.3 Additional CHP Estimated Savings (‘off peak’ electricity tariff) PARAMETER Cost of ‘on peak’ electricity Cost of ‘off peak’ electricity Cost of natural gas Electricity utilisation LTHW utilisation Availability hours (per annum)
PARAMETER
"ON PEAK"
RESULT 13.42 p/kwh 7.76 p/kwh 3.485 p/kwh 100% 40% 90%
"OFF PEAK"
Capital
TOTAL / MEAN £
Electricity Savings
£153,450
£44,366
£197,816
LTHW Savings
£37,668
£18,834
£56,501
CHP Gas Cost
(£131,479)
(£65,740)
(£197,219)
GROSS ENERGY SAVINGS Maintenance
£59,638
(£2,540)
£57,098
NET ENERGY SAVINGS Parameter Electricity CO2 Abatement (tCO2) LTHW CO2 Abatement (tCO2) Fuel CO2 Released (tCO2) Total CO2 Abatement (tCO2)
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(£20,000) £37,098 "On Peak"
"Off Peak"
Total / Mean
549.1
274.5
823.6
198.5
99.3
297.8
(692.9)
(346.4)
(1,039.3)
54.7
27.4
82.1
July 2014
6.4 Additional CHP Simple Payback Calculation (off peak electricity tariff) Additional CHP (MSB2) Supply & delivery (ENER-G Combined Power Ltd) Adaptations to existing CHP installation Installation & Commissioning Ancillaries (controls, BMS interface etc) Total estimated cost * Budget estimate **excludes M&E design fees
Simple payback calculation Total estimated capital cost Annual estimated energy savings Simple payback period 7.0
£210,000* £50,000* £100,000* £10,000* £370,000**
£370,000 £37,098 10 years
SUPPLEMENTARY COOLING CAPACITY 7.1
Gas Consumption Data
The heat generated by the CHP in day to day operation is sometimes referred to as ‘free heat’ because it is a by-product of the generation of electricity. The light red coloured bars on the chart represent the amount of gas consumed by the CHP for generating electricity and heat and the deep red coloured bars represent the quantity of gas consumed by the heating boilers for meeting the Hospital LTHW heating, domestic hot water and process steam demands. As can be seen from the following chart (figure 7.1) the heat output from the CHP being delivered to the hospital is reasonably consistent for January 2013 and accounts for approximately 40% of the total heat demand of the Hospital. In March 2013 the CHP contributed 36% of the total heat demand and in May 2013 the CHP contributed 48% of the total heat demand. Minimum and maximum external temperatures have been overlaid on the gas consumption charts. One would expect to see a fairly close correlation between the Hospital heating demands and recorded external temperatures.
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Figure 7.1 Gas Consumption Chart January 2013
The monthly gas demands (figure 7.1.1) show that demands for heat from the main boilers is significantly reduced in the summer months.
MONTHLY GAS DEMANDS (kwh) NOV 2012 - JULY 2013 4,000,000
CHP ELEC
3,500,000
CHP ELEC
CHP ELEC CHP HEAT BOILERS + STEAM
CHP ELEC CHP HEAT BOILERS + STEAM
CHP ELEC CHP HEAT BOILERS + STEAM
CHP HEAT
CHP ELEC
CHP ELEC
BOILERS + STEAM
500,000
BOILERS + STEAM
1,000,000
BOILERS + STEAM
1,500,000
CHP HEAT
2,000,000
BOILERS + STEAM
CHP ELEC
BOILERS + STEAM
CHP HEAT
2,500,000
CHP HEAT
3,000,000
CHP HEAT
0 Nov-12
Dec-12
Jan-13
Feb-13
Mar-13
Apr-13
May-13
Jun-13
Jul-13
Figure 7.1.1
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7.2
CHP heat output vs total heat demands AVG HEATING DEMAND
CHP HEAT OUTPUT
AVG NETT SPARE HEAT
MEAN OUTSIDE TEMP
30 MAY 2014
442 KW
919 KW
477 KW
12.2
31 MAY 2014
505 KW
919 KW
414 KW
12.8
01 JUNE 2014
556 KW
919 KW
363 KW
11.5
02 JUNE 2014
451 KW
919 KW
468 KW
13.7
03 JUNE 2014
554 KW
919 KW
365 KW
13.1
29 JUNE 2014
320 KW
919 KW
599 KW
13.5
30 JUNE 2014
497 KW
919 KW
422 KW
13.4
01 JULY 2014
343 KW
919 KW
576 KW
AVERAGE
459 KW
919 KW
460 KW
DATE:
230 KVA CHP TOTAL AVAILABLE HEAT ENERGY ABSORPTION CHILLER HEAT DEMAND AVG HOSPITAL HEAT DEMAND SUB-TOTAL
358 KW 818 KW 599 KW 459 KW 1,058 KW
AVAILABLE HEAT ENERGY
818 KW
NETT DEFICIT
240 KW
ADSORPTION CHILLER HEAT DEMAND AVG HOSPITAL HEAT DEMAND SUB-TOTAL
826 KW 459 KW 1,285 KW
AVAILABLE HEAT ENERGY
818 KW
NETT DEFICIT
467 KW
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By carrying out flow rate tests of the CHP secondary circuit and downloading historical temperature record data from the CHP control panel it was possible to determine the KW heating demands that were met by the CHP over a 5 day period. The cooling capacity of the Hospital may be increased by the introduction of thermal chiller with the primary energy being derived from the existing and additional CHP. However, the table above shows a nett shortfall of CHP heat to meet the total heating demands of the hospital and the heat load of the thermal chiller. The shortfall in CHP heat capacity shall be able to be met by the Hospital steam boilers but the shortfall is likely to increase when hospital heating demands grow i.e. in the winter, spring & autumn seasons. Ongoing data logging of the CHP secondary circuit water temperatures are recommended to be carried out further in order to assist with the chiller selection. 7.3
Adsorption or Absorption Water Chillers?
An article reprinted from the September 2009 online edition of Cogeneration & On-site Power Production provides an excellent description of the modes of operation, benefits and drawbacks of both adsorption and absorption water chillers. In summary the adsorption machine incorporates a dry desiccant in the form of naturally occurring and environmentally benign zeolite or silica gel and the absorption design utilise a liquid desiccant in the form of lithium bromide which is not environmentally benign. A significant cost premium is attached to the adsorption chiller for reasons of the design being not so well established and relatively few machines having been supplied. The adsorption design also require buffer vessels to be incorporated owing to the production of chilled water being intermittent. Proposals have been received from suppliers of both types of chiller designs and are included elsewhere in this report. A table has been included in the appendices which provides a summary of the principal characteristics for both types of chiller design so that an informed decision may be made on the most appropriate type of chiller design to meet the needs of the Hospital. The suppliers of the adsorption chiller (Weatherite Ltd) have advised the following details (table 6.9.1) concerning the estimated electrical demands of the equipment parasitic loads:
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PARASITIC LOAD
KW
ADSORPTION CHILLER
0.2 KW
PRIMARY PUMPS CHW
7.5 KW
SECONDARY PUMPS CHW
7.5 KW
PRIMARY COOLING PUMPS
30.0 KW
SECONDARY COOLING PUMPS
18.5 KW
HOT WATER PUMPS
18.5 KW
COOLING TOWER FANS
22.0 KW
TOTAL CONNECTED LOAD
104 KW
TOTAL ESTIMATED RUNNING LOAD
60 KW
Table 6.9.1
The estimated costs for the items:i. ii. iii. iv. v. vi. vii. viii. 7.4
supply of both types of chillers exclude the following Offloading costs (crane & temporary storage) Adiabatic dry cooler Pumps, fans & controls Small air compressor Installation Pipework interface with existing systems BMS interface Builders work in connection (BWIC)
Simple Payback Calculation
The following are simple payback calculations based upon the estimated capital costs for both chiller types and the electricity/gas tariffs currently in force: 7.5
Option ‘A’ Adsorption chiller (single rate tariff)
Adsorption Chiller Supply & delivery (Weatherite Ltd) Adiabatic dry cooler Installation & Commissioning Ancillaries Total estimated cost * Budget cost ** excludes M&E design fees
£195,000 £35,000 £50,000* £15,000* £295,000**
Annual energy costs saved (see note below) 9.45 hours x MEA industrial tariff (£0.1342) x 423kw x £146,986 274 hours Less parasitic demands for adsorption chiller: £17,650 8 hours x MEA industrial tariff (£0.1342) x 60kw x 274 days. Gross annual saving £129,336 P a g e | 15
July 2014
Simple payback calculation Total estimated cost Gross annual saving Less annual maintenance costs Less gas costs to meet CHP heat shortfall (467kw x 8,736 hrs x £0.035 = £142,790) Simple payback period
£295,000 £129,336 £3,320 £142,790
£-16,774 NO PAYBACK
7.5.1 Option ‘A1’ Adsorption chiller (off-peak tariff) Adsorption Chiller Supply & delivery (Weatherite Ltd) Adiabatic dry cooler Installation & Commissioning Ancillaries Total estimated cost * Budget cost ** excludes M&E design fees
£195,000 £35,000 £50,000* £15,000* £295,000**
Annual energy costs saved 1 M of ice storage = 93kwh. 43 M3 = 4,000kwh = 9.45hrs charging 8 hours x off-peak rate (£0.0776) x 423kw x 274 £71,952 days 1.45 hours x on-peak rate (£0.1342) x 423kw x £22,553 274 days Less parasitic demands for adsorption chiller: 8 hours x on-peak rate (£0.1342) x 60kw x 274 £17,650 days Gross annual saving *Assume 9 months per annum cooling cycle 3
£94,505
£76,855
Simple payback calculation Total estimated cost Gross annual saving Less annual maintenance costs Less gas costs to meet CHP heat shortfall (467kw x 8,736 hrs x £0.035 = £142,790) Simple payback period 7.6
£295,000 £76,855 £3,320 £142,790
NO PAYBACK
Option ‘B’ Absorption chiller (single rate tariff)
Absorption Chiller Supply & delivery (Carrier Sanyo Ltd) Adiabatic dry cooler Installation & Commissioning Ancillaries Total estimated cost * Budget cost ** excludes M&E design fees
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£-69,255
£75,000 £35,000 £25,000* £15,000* £150,000**
July 2014
Annual energy costs saved (see note below) 9.45 hours x MEA industrial tariff (£0.1342) x 423kw x £146,986 274 days* Less parasitic demands for adsorption chiller: £17,650 8 hours x MEA industrial tariff (£0.1342) x 60kw x 274 days Gross annual saving £129,336
Simple payback calculation Total capital estimated cost Gross annual saving £129,336 Less annual maintenance costs £2,810 Less gas costs to meet CHP heat shortfall £73,384 (240kw x 8,736 hrs x £0.035 = £73,384) Simple payback period
£150,000
£53,142 2.8 years
7.6.1 Option ‘B1’ Absorption chiller (off-peak tariff) Absorption Chiller Supply & delivery (Carrier Sanyo Ltd) Adiabatic dry cooler Installation & Commissioning Ancillaries Total estimated cost * Budget cost ** excludes M&E design fees
£75,000 £35,000 £25,000* £15,000* £150,000**
Annual energy costs saved 1 M3 of ice storage = 93kwh. 43 M3 = 4,000kwh = 9.45hrs charging 8 hours x off-peak rate (£0.0776) x 423kw x 274 £71,952 days* 1.45 hours x on-peak rate (£0.1342) x 423kw x £22,553 274 days Less parasitic demands for adsorption chiller: 8 hours x on-peak rate (£0.1342) x 60kw x 274 £17,650 days* Gross annual saving *Assume 9 months per annum cooling cycle
Simple payback calculation Total capital estimated cost Gross annual saving £76,855 Less annual maintenance costs £2,810 Less gas costs to meet CHP heat shortfall £73,384 (240kw x 8,736 hrs x £0.035 = £73,384) Simple payback period
£94,505
£76,855
£150,000
£661 227 years
Note: The saving in electricity running costs may be calculated as the annual cost of electricity that would be paid by providing a further 423kw mechanical chiller and ice storage vessel of the same specification as presently exists.
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8.0
WATER COOLING It should be noted that both adsorption and absorption chiller designs require a cooling tower or an adiabatic dry cooler to be incorporated into the installation in order to reject the low grade heat from the condenser cycle. A water operated cooling tower of either forced draft or induced draft design presents an inherent risk of legionella unless a properly managed maintenance regime is implemented. An adiabatic dry cooler, however, does not carry an intrinsic risk of legionella because of the closed circuit type of design. For reasons of the elimination of the risk of legionella Epsilon Consultants (IOM) ltd recommend the selection of a dry cooler.
9.0
NEW PLANTROOM LOCATION The chiller, water cooling equipment, ancillary pumps, buffer vessels and the additional CHP serving MSB2 are proposed to be located in a solidly built plantroom structure outside the Hospital energy centre. Pipework and cables linking the plantroom with the existing M&E services in the energy centre are proposed to be routed underground in a concrete lined, accessible trench. A drawing is included in the Appendices showing the proposed location of the new plantroom. Design & construction costs for the new external plantroom have not been included in this report.
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APPENDICES
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