Enman Pty Ltd Energy Management Consultants

Transcription

1 Enman Pty Ltd Energy Management Consultants Feasibility Study of Hotel Energy Management System for Mercure Hotel Sydney April 2013 V-2.0 Experienced, Professional People at Your Service Table of Contents

2 Executive Summary... 3 Introduction... 3 Hotel Energy Management System Overview... 3 Savings Summary... 3 NABERS rating... 5 Current rating... 5 Project rating Improvement... 5 Energy Management System description... 5 Energy Management System Functionality Energy use Energy Saving Opportunities Implementation of a Building Management System (BMS) BMS Installation Savings Enthalpy Based Economy Cycle with CO2 Control Energy saving Optimal Fan Speed Control Energy saving Optimal Pump Speed Control Energy saving Optimal Chiller Control Optimal Chilled Water Temperature Set Point Optimal Condenser Water Temperature Set Point Optimal Chiller Operation and Load Cycling Energy saving Demand Management and Housekeeping Demand reduction Energy saving Project Cost Breakdown Appendix I: Site Description Chillers Cooling Towers Pumps Air Handling Units Ventilation Fans Schwartz Family Co. Page 2 of 18 Enman Pty Ltd

3 1.0 Executive Summary.1 Introduction Enman Pty Ltd has undertaken this technical study for the Mercure Hotel, Sydney to ascertain the economic and technical viability to implement this unique Hotel Energy Management System. This will improve energy efficiency, reduce energy consumption and improve the environmental footprint of the hotel. Enman Pty Ltd was commissioned by the Schwartz Family Corporation to do so. Mercure Hotel, Sydney hotel is a 517 room hotel located in Sydney. The proposed EMS will include the installation of a BMS as well as an upgrade on this system to include high intelligence technology and application engineering which will significantly increase energy efficiency. Table 1. Summary of Site Parameters Rated Hotel Quality Star Rating (AAA) Site Rating 4 Stars Guest Rooms 517 Conference Room Seats 1,262 Electricity Consumption for 12 month 4,685,242 kwh Natural Gas Consumption for 12 months 6,552,571 MJ Current Energy Rating (NABERS) 3.5 Stars.2 Hotel Energy Management System Overview Enman s Hotel Energy Management System (HEMS) is an advanced control system that monitors, automates and optimises settings and operations in order to save energy, money and greenhouse gas emissions throughout the hotel. The system is adapted to complement and meet the requirements of each individual hotel. The main equipment that the system aims to control are the chillers, pumps, cooling towers, air handling units, kitchen exhaust fans and car park fans with variable speed drives. Enman uses their advanced optimisation technology to ensure that comfort conditions are maintained while energy use of this equipment is significantly reduced. The EMS also has a demand management function that limits the peak demand of the hotel. This can significantly reduce the monthly electricity bill..3 Savings Summary The energy cost reduction from the implementation of the EMS is expected to be around 25% of the total electricity costs (including demand costs) of the hotel. The following table summarises the outcomes of the study conducted Schwartz Family Co. Page 3 of 18 Enman Pty Ltd

4 Table 2. Summary of expected project energy savings Summary Value Units Electricity saving 979,968 kwh/year Demand saving 150kVA/month Energy Cost Saving 152,714$/year Green House Reduction 1039t Co2-e/year Expected ESC Revenue 25,969$/year Total Cost Savings (Inc. ESC) $178,683$/year Expected project cost $406,350$ Simple payback 2.27years It should be noted that the current average cost of electricity for this hotel is around $ / kwh. This price has been used for the cost saving analysis. Table 3. Energy Saving Summary Project Description Energy Saving Energy Cost Saving GHG Reduction ESC* Revenue Total Cost Saving kwh / year $ / year t CO2-e $/y $/y 3.1 Implementation of a BMS 266,122 $38, $7,052 $45, Enthalpy Based Economy Cycle with CO2 control 49,253 $7, $1,305 $8, Optimal Fan Speed Control 192,000 $27, $5,088 $33, Optimal Pump Speed Control 65,572 $9, $1,738 $11, Optimal Chiller Control 298,502 $43, $7,910 $51, Optimal Cooling Tower Fan Speed Control 14,815 $2, $393 $2, Demand Management - $10, House Keeping 93,705 $13, $2,483 $16,119 Total 979, ,714 1,039 25, ,574 * ESC Value was taken to be $25/t CO2 e. Further details of the savings are in section 3.0 of this report. Schwartz Family Co. Page 4 of 18 Enman Pty Ltd

5 .4 NABERS rating.4.1current rating The site was assessed in accordance with the NABERS energy validation protocol for hotels, and fits within the stated hotel classifications. A rating has been conducted for the rating period 1/05/2011 to 30/04/2012. Currently the Mercure Hotel has a NABERS rating of 3.5 stars. Equating to emissions of 10,444 kg CO2/room/year. For a hotel similar to the Mercure hotel in Sydney CBD the benchmark GHG emissions are 15,404 kg CO2/room/year. This is the average hotel performance for a benchmark comparable to the Mercure hotel..4.2project rating Improvement If all above stated projects are undertaken, the projected savings will increase the NABERS rating of the hotel to 4 stars. Equating to emissions of 8,435 kg CO2/room/year. A reduction of carbon intensive emissions by 2,009 kg CO2/room/year. 1.5 Scope of Project.1 Energy Management System description Figure 1 - EMS Architecture Schwartz Family Co. Page 5 of 18 Enman Pty Ltd

6 HEMS This is the black box, based in a JACE6, which is a Tridum Niagara based system. This will provide all energy management and optimal control functions and it will be interfaced with the electricity meters. The EMS Jace6 will communicate with the BMS to receive all plant information required for optimal control. The optimal control commands are then sent back to the BMS for direct control of the equipment. BMS A Building management system will be installed at the hotel. All plant and field instruments including variable speed drives (VSDs) are monitored and directly controlled by the BMS. The BMS and EMS will operate in handshake mode. The proposed BMS is a Tridum based Niagara system similar to the Holiday Inn system at Mascot. This BMS is a non-proprietary system which can be maintained by many different companies in Sydney. Operator Station The standard BMS operator station through a PC is used as the operator station for the BMS and EMS. All EMS running parameters and reporting functions will reside in the BMS PC. VSD The VSDs will be installed on fans and pumps where feasible. They will communicate with the BMS and directly control the speed of the motors. The VSD price includes ABB branded VSDs, which are currently installed at Holiday Inn, Mascot..2 Energy Management System Functionality A central building management system will be installed to control chillers, pumps, cooling towers, boilers, fan coil units and ventilation fans. This will allow for the implementation of an energy management system. The recommended energy management functions are as follows Installation of New VSDs for Optimal Fan Speed Control on o AHU Coffee Lounge kw o AHU Reception Area kw o AHU South check-in kw o AHU Kitchen kw o AHU Rest Centre kw o AHU Rest NE Perim kw o AHU Admin Area kw o FCU SW 15 kw o FCU NE 15 kw o Admin Area VAV kw o Admin Area VAV kw o Kitchen Exhaust KEF 18.5 o TEF-1 15 kw o TEF kw o TEF-3 11 kw o Condenser Fan 3 kw Improved Car Park Fan Speed Control (VSD Existing) o Car Park Supply CSF1 30 kw o Car Park Exhaust CEF1 55 kw Optimal Pump speed control for the following pumps (VSD Existing) Schwartz Family Co. Page 6 of 18 Enman Pty Ltd

7 CWP kw CWP kw CWP kw CHWP1 30 kw CHWP2 22 kw CHWP3 30 kw Optimal Cooling Tower Fan Speed Control (VSD Existing) o CT fan 7.5 kw o CT fan 7.5 kw Optimal Chiller Control This is an optimal supervisory control function for the chillers to operate at maximum energy efficiency at all times. These functions are: Optimal Chilled Water Temperature Reset Optimal Condenser Water Temperature Reset Optimal Chiller Selection, Loading and Load Cycling Control Demand Management and Housekeeping. (This may require resetting of the current demand capacity by the energy distributor) Schwartz Family Co. Page 7 of 18 Enman Pty Ltd

8 2.0 Energy use The hotel s total energy accounts for the twelve month period ending May 2012 are summarised in the following tables. Table 1 summarises the electrical accounts and Table 2 summarises the natural gas accounts for the same twelve month period. Table 4 - Electricity consumption information Total Electrical consumption Information for the stated rating period Total Electrical Energy 4,685,242 kwh Maximum Contract Demand 1165 kva Total Electrical Energy Cost $ 681,796 Average Cost $/kwh Approximately 60% of the sites total energy costs are attributed to electrical usage. The Mercure hotel consumes 6,552,571 MJ of Natural gas per year. The following table and figure shows the electrical energy consumption by the major end use areas. The end use areas only include those components which are regarded for the Hotel Energy Management Control System (EMS) project. Table 5: End Use Energy Consumption (Estimated) of equipment not controlled by EMS End Use Consumption kwh/year % Chiller 836, % Pumps & Cooling Tower 655, % AHU s 520, % Electric Duct Re-Heat 511, % Exhaust Fans 631, % Supply Fans 178,319 4 % Other including lighting and lift 1,352,150 29% Total 4,685, % Schwartz Family Co. Page 8 of 18 Enman Pty Ltd

9 Figure 2- End Use Energy Consumption (Estimate) of equipment not controlled by EMS It should be noted from the above presentation that the term Other means the rest of the electrical energy being used throughout the Hotel. This includes lighting, kitchen appliances, room FCU s, in-house power, lifts and any equipment which has not been considered for the EMS project. Schwartz Family Co. Page 9 of 18 Enman Pty Ltd

10 3.0 Energy Saving Opportunities The energy management system (EMS) is a supervisory and optimal control system. This system consists of a number of individual control functions which will significantly reduce the amount of energy used by the equipment as well as improve the performance of the operation. The advantages of the EMS functions over the existing system, cost and saving analysis for each function is outlines as follows 3.1 Implementation of a Building Management System (BMS) Currently the building automation is based on local discrete control. There is no functional BMS on site. A BMS allows for centralised control of all major equipment; providing a platform to monitor and control energy use. The installation of a BMS is required to install a EMS; the EMS will integrate with the BMS utilising the same communication routes to control the equipment. The installation of a BMS will also include installation direct digital control(ddc)at the site. Currently, the heating and cooling system of the air handling units are controlled by stand alone, old style analogue control systems. It is proposed to replace these existing controllers by DDC s using the proposed BMS. The advantage of such control is that the heating and cooling valves are controlled more accurately, can be better tuned and it stops any simultaneous heating and cooling. This will reduce the energy use of the chillers and boilers significantly BMS Installation Savings Replacing the existing discrete, local control with a fully tunned BMS system will yield around 8% savings of the sites total HVAC electricity consumption. Energy Saving = 3,262,522 8% = 268,651kWh/year Cost Saving = $39,094/year GHG Saving = 285t CO2 -e/year 3.2 Enthalpy Based Economy Cycle with CO2 Control Mercure Hotel, Sydney has no economy cycle fitted to any of the air handling units. It is recommended that enthalpy based economy cycle be fitted to the air handling units in Table 6. Enthalpy based economy cycle is the most accurate and effective economy cycle; it will significantly reduce the energy consumption of the chillers. Each of the six units selected to have an economy cycle installed will be fitted with CO2 monitoring and relative humidity temperature sensors to provide demand based fresh air intake. The outside air and the return air dampers will be modified to allow this control. Table 6 - Proposed Fan Coil Units for Enthalpy Based Economy Cycle AHU Location Motor size Schwartz Family Co. Page 10 of 18 Enman Pty Ltd

11 3-1 Banquet 2 Perimeter Banquet 2 Centre Breakout Area Kitchen Fresh Air Office & Pre-Function Admin Area Energy saving The total annual energy use of the chillers and associated pumps is around 1,492,508 kwh. It is estimated that these fan coil units use 11% of the chiller load. It is expected that the savings from the economy cycle and demand based fresh air is 30% of the chiller load used by the units. Therefore the total expected energy savings from installing enthalpy based economy cycle is: Energy Saving = 1,492,508 11% 30% = 49,253kWh/year Cost Saving = $7,176/year GHG Saving = 52t CO2 -e/year 3.3 Optimal Fan Speed Control All the supply air fans at this site are fitted with fixed speed motor. The volume of air supplied to the building is constant, regardless of varying heating or cooling load or occupancy of the building. It is proposed that the fans listed in Table 7 are installed with variable speed drives and controlled by feed forward control. The EMS will control the fans speed set point using a sophisticated control algorithm which is based upon occupancy type, occupancy rate and weather conditions. Table 7: Recommended Fans for VSD Installation Fan Level Model Location Motor Size (kw) AHU 1.1 Ground SR3000 Coffee Lounge 4 AHU 1.2 Ground SR4000 Reception 4 AHU 1.3 Ground SR3000 South Check-Inn 3 AHU 2.1 Level 1 SR4000 Kitchen 7.5 AHU 2.2 Level 1 SR4000 Rest Centre 7.5 AHU 2.3 Level 1 SR2000 Rest NE Perimeter 3 AHU 3.10 Level 2 Unknown Admin Area 3 AHU 16.1 Level 16 FCV1250 Guest Room levels 15 AHU 16.2 Level 16 FCV1250 Guest Room levels 15 TEF-1 Level 16 Unknown Room Toilet Exhaust 15 TEF-2 Level 16 APA0804 Toilet Exhaust to Rooms 5.5 TEF-3 Level 16 APA1004 Toiler Exhaust to Rooms 11 Schwartz Family Co. Page 11 of 18 Enman Pty Ltd

12 KEF -2 40L Kitchen 18.5 VAV 3-1 Unknown Admin Area Perimeter 4 VAV 3-2 Unknown Admin Area Centre 6 Condenser Fan Unknown Condenser Room 3.1 Energy saving The expected energy savings from these fans is 40% of the current energy consumption. Total electricity consumption by the above listed fans is around 480,000kWh/ year. The energy saving with regard to this function is, therefore: Energy Saving = 480,000 40% = 192,000kWh/year Cost Saving = $27,900/year GHG Saving = 204t CO2 -e/year 3.4 Optimal Pump Speed Control The hotel has three primary chilled water pumps and three condensing water pumps. These pumps currently have new VSDs operating under a pre-set differential pressure. It is proposed that these pumps be controlled by optimal speed control algorithm. The speed of the pumps will be controlled to provide optimal flow based upon cooling or heating load. The existing differential pressure will be used for flow control. Figure 3 shows an example of optimal pump speed control for a chilled water or condenser water pump. VSD (with PID) Measurement Set point S.P. = function (cooling load) ΔPTX Speed Chiller Pump Figure 3 - Example Optimal Pump Speed Control System Table 8 shows the pumps that are recommended to be controlled by VSD and optimal pump speed control. Schwartz Family Co. Page 12 of 18 Enman Pty Ltd

13 Table 8: Pumps proposed for VSD Control Pump Model Location Motor size CNWP1 (Existing VSD) E Rooftop Plant room 18.5 CNWP2 (Existing VSD) E Rooftop Plant room 18.5 CNWP3 (Existing VSD) E Rooftop Plant room 18.5 CHWP1 (Existing VSD) E Rooftop Plant room 30 CHWP2 (Existing VSD) E80-40 Rooftop Plant room 22 CHWP3 (Existing VSD) E Rooftop Plant room 30 CT Fan 1(Existing VSD) SDC-U-500ASC Rooftop Plant room 7.5 CT Fan - 1(Existing VSD) SDC-U-500ASC Rooftop Plant room Energy saving The expected energy saving of these pumps is 10% of the current energy consumption. Total electricity consumption by the above listed pumps is around 655,724 kwh / year. The energy saving with regard to this project is, therefore: Energy Saving = 655,724 10% = 65,572kWh/year Cost Saving = $9,542/year GHG Saving = 70t CO2 -e/year 3.5 Optimal Chiller Control Optimal Chilled Water Temperature Set Point Currently the Chilled water temperature set point is manually fixed at the local chiller control panel. It is recommended to install a remote chilled water temperature set point through the BMS. The chilled water temperature will be set at an optimal temperature to operate the chiller more energy efficiently. This uses a special control algorithm to calculate the chilled water temperature continuously to get the maximum benefit for this function. The average chilled water temperature is expected to operate at approximately 2 C higher than the current set point. This function is expected to save 7% of the existing chiller energy..2 Optimal Condenser Water Temperature Set Point The EMS will calculate the optimal set point of the cooling water utilising a control algorithm based upon ambient air wet bulb temperature and compressor loading (optional). This is to minimise the combined cooling tower fan and chiller compressor energy use. The current VSDs will be utilised on the fans listed in Table 10. Schwartz Family Co. Page 13 of 18 Enman Pty Ltd

14 Table 9 - Cooling Tower Fan Details Fan Model Location Motor size Cooling Tower 1 SDC-U-500ASC Roof 7.5 kw Cooling Tower 2 SDC-U-500ASC Roof 7.5 kw It is expected that there will be of 24% of the current Cooling Tower energy consumption. It is expected that the saving from the compressor is around 6% of the chiller energy Optimal Chiller Operation and Load Cycling This function is to provide optimal selection, loading and cycling of chillers to minimise chiller energy consumption. During very low load condition the operating chiller will be put into cycling mode. The chiller cycling mode ensures that the chiller does not run at very low efficiency and turns the chiller off wherever possible. This is the most efficient component of optimal chiller control and it is expected that the saving will be around 7% of the existing chiller energy Energy saving Total electricity consumption by chillers and pumps is around 1,492,508 kwh / year. The total chiller energy saving with regard to the Optimal Chiller Control is around 20%. Energy Saving = 1,492,508 20% = 298,502kWh/year Cost Saving = $43,438/year GHG Saving = 316t CO2 -e/year The total energy consumption of the two on site Cooling Towers is 61,728kWh/year. A saving of 24% of this load is expected. Energy Saving = 61,728 24% = 14,815kWh/year Cost Saving = $2,156/year GHG Saving = 16t CO2-e/year Schwartz Family Co. Page 14 of 18 Enman Pty Ltd

15 3.6 Demand Management and Housekeeping The demand management and housekeeping will provide two functions: Demand Management The EMS PLC will interface with the electricity supply meter directly. This will monitor the energy pulse, time pulse and KVARh pulse. The EMS will use this data to calculate electricity demand every minute. The achieved demand will be compared to the set Target demand and the remaining demand will be estimated. If the remaining demand exceeds the Target demand the EMS will reduce electricity load by various methods, which are: Load shedding of the chillers Resetting the chilled water temperature Resetting the fan speed of the air handling units The load will only be controlled within a specific demand window. This demand window is a time frame set by the electricity network provider when the peak demand charge is applicable. Housekeeping The EMS provides a comprehensive energy performance monitoring and reporting function which is important for the management. This information can be used to understand the energy use of the hotel and identify any misuse of energy. It can also be used to improve tuning of the utility energy control system Demand reduction It is expected that this system will reduce demand by approximately 150 kva on an average per month. This equates to a cost saving of approximately $10,163/ year (Current charge for the demand is $ / kva per month). This may require resetting of the current demand capacity by the energy distributor Energy saving The energy saving from a good housekeeping is expected to be 2% of the site s total energy consumption. Energy Saving = 4,685,242 2% = 93,705kWh/year Cost Saving = $13,636/year GHG Saving = 99t CO2 -e/year Therefore the total saving from this component of this EMCS project is around $23,744/ year. Schwartz Family Co. Page 15 of 18 Enman Pty Ltd

16 Project Cost Breakdown Component Cost Niagara Based BMS System $133,650 Mechanical Works(AHU Modification) & Supply of VSDs $161,600 Additional Field Equipment (as Free Issue for Mechanical Work) $17,600 Hotel Energy Management Control System $55,000 Electrical Meter Connection $3,500 Project Management & Engineering $35,000 Total Project Cost $406,350 NOTE: this cost is exclusive of GST Schwartz Family Co. Page 16 of 18 Enman Pty Ltd

17 Appendix I: Site Description The Holiday Inn, Sydney Airport is a 247 room Hotel situated in Mascot, Sydney. There is no central or building management control at this hotel. The HVAC equipment is controlled via local controllers. There are no variable speed drives or economy cycle at the site. Chillers Feasibility study of Hotel Energy Management System April 2013 Chiller Equipment Compressor type Model Location Motor size Chiller 1 Chiller 2 YORK Trane Series R Screw Helical Rotary YSDBCB S45 CFC Rooftop plant room RTHD-C2D4E4 Rooftop plant room 250 kw 160 kw The two chillers are 10 stage modular chillers Normally one chiller is in operation Cooling Towers Cooling Tower Make Model Location Motor size CT-1 SDC-U-500ASC Roof 7.5 kw CT-2 SDC-U-500ASC Roof 7.5 kw Pumps Pump Make Model Location Motor size Chilled water pump 1 E Rooftop plant room 30 kw Chilled water pump 2 E80-40 Rooftop plant room 22 kw Chilled water pump 3 E Rooftop plant room 30 kw Condenser water pump 1 E Rooftop plant room 18.5 kw Condenser water pump 2 E Rooftop plant room 18.5 kw Condenser water pump 3 E Rooftop plant room 18.5 kw Air Handling Units AHU Location Motor Size 1-1 Coffee Lounge Reception South Check-in Kitchen Rest Centre Rest NE Perimeter Chef s Office Banquet 2 Perimeter Banquet 2 Centre Breakout Area Service Corridor 1.1 Schwartz Family Co. Page 17 of 18 Enman Pty Ltd

18 3-5 Banquet Meeting Room Meeting Room Meeting Room Managers Offices Admin Area Meeting Room FCU SW Guest Corridors FCU NE Guest Corridors 15 The fan coil units are controlled using local controllers that measure the room temperature of the serviced area. They also set the time schedules for the units Ventilation Fans Fan Model Location Motor Size TEF-1 APA1004 Rooms 15.0 TEF-2 APA0804 Rooms 5.5 TEF-3 APA1004 Rooms 11 TEF-4 ILD354 Basement 0.3 TEF-5 ILD354 Level TEF-6 ILD404 Level TEF-7 ILD404 Level SP-1 APA1004 Fire Stair 1 11 SP-2 APA0804 Fire Stair RF-1 APA0714 Stair Relief 2.2 RF-2 APA0804 Stair Relief 5.5 EF-2-1 APA1006 Cool Room Vent 4.0 RF-3 APA1006 Level 3 Relief 4.0 KEF 40L Kitchen Exhaust 18.5 CSF-1 44L Car park Supply 30.0 CEF-1 60L Car park Exhaust 55.0 SP-3 APA0714 Fire stair SP-4 APA0714 Fire Stair SF-CP-1 ILD454 Locker Supply 0.7 EF-CP-2 T3-200 Sewage Ejector SF-B-1 ILD454 Base South Supply 1.3 EF-B-1 T3-200 Basement South 1.3 SF-B-2 ILD504 Base North Supply 0.7 EF-B-2 ILD504 Sewage Ejector EF-B-3 ILD354 Garbage Exhaust 0.3 EF-B-4 T3-200 Gas Meter Room EF-PR-1 RVE0634 Plant Room 2.2 EF-PR-2 RVE0804 LMR EXH 5.5 SF-PG-1 APP0634 Pool Supply 2.2 EF-PG-1 APP0634 Pool Exhaust 2.2 Schwartz Family Co. Page 18 of 18 Enman Pty Ltd