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Demand Flow Chiller Plant OptimisationRobina Hospital Case Study

September 2015

02-09-2015 KM / Siemens Building Technologies

• Facility Overview• Project Motivations• Evaluation & Assessment• Optimisation Process• Results

Robina Hospital Chiller Plant OptimisationTable of Contents

Kieran McLeanBusiness DevelopmentSiemens Ltd.


Robina Hospital Chiller Plant OptimisationFacility Overview

Robina Hospital is the 6th largest hospital in Queensland with 364-beds anda suite of inpatient and outpatient services.

The facility has undergone constant expansion over the past 15 years:

• 2000 – Constructed as a private hospital offering some public services• 2002 – Acquired by QLD Government• 2007 – Stage 1 expansion adding 25 beds• 2012 – Stage 2 & 3 expansions doubling number of beds

► FacilityOverview

► ProjectMotivations

► Evaluation &Assessment

► OptimisationProcess

► Results


Robina Hospital Chiller Plant OptimisationFacility Overview





► Results

AX Building Chiller Plant1x Air-Cooled Chiller

Original Central Chiller Plant3x Reciprocating Water Cooled Chillers

(768kWr)

Link between Chiller Plants

New Central Chiller Plant3x Centrifugal Water

Cooled Chillers (2500kWr)


Robina Hospital Chiller Plant OptimisationProject Motivations

1. Simplification of Chilled Water System Operation

2. Improve facility energy efficiency

3. Reduce maintenance requirements of 3x Chiller Plants

4. Improve Humidification Control of Operating Theatres





► Results


Robina Hospital Chiller Plant OptimisationEvaluation and Assessment – Chilled Water Sub-Systems

The five major energy consuming sub-systems of the Chilled Waternetwork are:

1. Chillers2. Chilled Water Pumps3. Condenser Water Pumps4. Cooling Tower Fans5. Air Handing Units





► Results

Demand Flow optimises the performance of all energyconsuming sub-systems holistically.


Robina Hospital Chiller Plant OptimisationOptimisation Process

• 3 month project implementation period (July – September)

• Installation of:• Variable Speed Drives for Condenser Water Pumps• Cooling Tower Isolation Valves• High accuracy differential pressure and temperature sensors

• Commissioning of:• Demand Flow control algorithm• 12 months system fine tuning

• Continuous supply of chilled water critical for operating theatres and MRI





► Results


Robina Hospital Chiller Plant OptimisationOptimisation Process – Demand Flow™ Commissioning

ChillersOptimised pressure andtemperature setpoints.

Increased operating times atchiller ‘sweet-spot’.

PumpsVariable speed control of allchilled water and condenserwater pumps.Removes system bypassesto reduce excessive pumpingenergy.

Cooling TowersOptimised cooling tower flow,variable speed fan controland staging.


Robina Hospital Chiller Plant OptimisationResults – Facility Improvements

• Improved humidification control of operating theatres

• Increase in deliverable plant capacity

• Effective management of chiller lift

• Eliminates refrigerant flow issues at low load conditions

• Consolidation of Chilled Water Plants


Robina Hospital Chiller Plant OptimisationResults – System Efficiency Improvement

Source: "All Variable Speed Chiller Plants", ASHRAE Journal, September 2001

0.57.0

0.65.9

0.75.0

0.84.4

0.93.9

1.03.51

1.13.2

1.22.9

1.32.7

Standard CodeBased Chiller Plants

New Technology,

All-Available Speed

Chiller Plants

High-Efficiency,Optimized

Chiller Plants

Older

Chiller

Plants

Chiller Plants with Repairable Design orOperational Problems

Excellent Good Fair Needs Improvement

Pre-Optimization(Annual Average 0.93 kW/Ton)

(Annual Average System COP 3.8)

Post-Optimization(Annual Average 0.66 kW/Ton)

(Annual Average System COP 5.3)

kW/ton *

COP *

(Annual Average)

* Includes Chiller,Pumps and CT FansCombined


Robina Hospital Chiller Plant OptimisationResults – First 8 Months of Savings

• 26% Saving in Chiller Plant Consumption

• 676,216 kWh saved (85% of annual target)

• Reduction of 554 Tonnes of CO2 emissions

• Anticipated payback of 2.5 – 3 years aheadof a 3.3 year guarantee


Demand Flow™Case Study – Robina Hospital

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100,000

200,000

300,000

400,000

500,000

600,000

700,000

800,000

900,000

Nov-14 Dec-14 Jan-15 Feb-15 Mar-15 Apr-15 May-15 Jun-15 Jul-15 Aug-15 Sep-15 Oct-15

Cumulative Target vs. Actual Savings (kWh)

Cumulative Target Cumulative Actual Annual Target


Kieran McLeanDemand Flow – Business DevelopmentE-mail: [email protected]

Any Questions?

Robina Hospital Chiller Plant OptimisationContact page

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