Energy & Heat Transfer in Healthcare HVAC

Energy & Heat Transfer in Healthcare HVAC Shawn Wilson, PE TME, Inc. swilson@tmecorp.com 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 1

Why target HVAC Systems? Shifting the Paradigm Agenda Controls are the Key 4 Opportunities Chilled Water Pumping Cooling Tower Relief Air Handler Controls, Resets Air Terminal Controls, Troubleshooting Closing, Q&A 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 2

Hospital HVAC Unique regulatory requirements for temperature and RH, airflow, and pressure relationships. Special applications (Surgery, Lab, Pharmacy, Sterile Processing etc ) Energy intensive facilities. Complex Systems, Complex Controls 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 3

Hospital Operating Costs 10% 3% 7% People Supplies 20% 60% Debt Service Energy Other 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 4

Hospital Business Environment Higher Costs Lower Revenues Insufficient Margins for Reinvestment Mounting Backlog of Deferred Maintenance 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 5

Average $4.09/SF Hospital Energy Costs

Hospital Operating and Maintenance Budgeting Typical Hospital Operating and Maintenance Budget ($7 to $12 per SF) Energy 51% Staffing 27% 14% 8% Service Contracts Materials 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 7

Hospital Operating and Maintenance Budgeting Reduced Operating Budgets Staffing Levels are already too Low Staffing 27% Energy 51% 14% 8% Service Contracts Materials 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 8

Hospital Operating and Maintenance Budgeting Reduced Operating Budgets Staffing Levels are already too Low Higher Material Costs 27% Energy 51% Staffing 14% 8% Service Contracts Materials 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 9

Hospital Operating and Maintenance Budgeting Reduced Operating Budgets Staffing Levels are already too Low Higher Material Costs Higher Service Contract Costs Energy 51% Staffing 27% 8% Materials 14% Service Contracts 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 10

Hospital Operating and Maintenance Budgeting Reduced Operating Budgets Staffing Levels are already too Low Higher Material Costs Higher Service Contract Costs Energy Costs must be Reduced Energy 51% Staffing 27% 14% 8% Service Contracts Materials 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 11

Energy Use In Hospitals 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 12

Selecting Systems and Equipment based on First Cost Using the Same Design for Every Project Conservative Over-Sizing of Equipment Current Paradigm Selecting Systems and Equipment without Considering Current and Future Utility Rates Control Systems Designed by Control System Manufacturers (not the Engineer) Commissioning included but often becomes construction phase QC and documentation exercise. 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 14

Current Best Practices Don t Always Yield High Performance LEED Efficient Design Standard Commissioning 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 15

LEED Certification Some Buildings not Living up to Green Label By Mirya Navarro August 30, 2009 LEED Buildings are no more Energy Efficient than their Peers More than half of LEED Buildings not eligible for Energy Star Label 15% of LEED Buildings have an Energy Star Rating less than 30 LEED is not Bad 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 16

Standard Commissioning LEED Certified Facilities have been Commissioned Many low Performing Hospitals were Commissioned Standard Commissioning is not bad 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 17

Potential Causes of Low Performance Energy Efficient Features are frequently Value Engineered out of the Project Systems are too complex for O&M Staff to Operate and Maintain Drive By Commissioning does Occur Facility Performance is not Measured and Verified Commissioning Agent Design Reviews are restricted to Commissionability Only O&M Staff have traditionally focused on Regulatory Compliance, Infection Rates, Comfort, and not Energy Efficiency 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 18

Potential Causes of Low Performance Control System Programming is not Consistent with the Design Intent Energy Management Systems are under Utilized Air Terminal Air Flow Setpoints are not Programmed in Correctly O&M Staff Training by Contractors does not Focus on Energy Conservation CxA is not Responsible for Building Performance O&M Staff are not Vested in a Positive Outcome Excess Simultaneous Heating and Cooling 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 19

Shifting the Paradigm Albert Einstein s Definition of Insanity: Doing the same thing over and over again and expecting different results. 12/5/201 HAAHE/TAFHM Facility Manager Basic Training 20

ASHE s Commissioning Guidelines and Handbook Meeting the Energy Efficiency Goals is not Optional Current Best Practices don t always Work Causes of Low Performance are Known ASHE s Commissioning Guidelines and Handbook focus on Meeting Facility and Project Energy Efficiency Goals 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 21

Construction Costs and Operating Costs must be Considered Holistically New Paradigm Minimize Reheat Create Synergy between Systems that Remove and Generate BTUs Pay Attention to the Control Programming 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 22

Setting the Energy Efficiency Goal If you aim at nothing, you ll hit it every time. Zig Ziglar 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 23

Benchmarking EPA Target Finder Weather Adjusted Occupancy Adjusted Free Service Internet Based Simplified Input Percentile Ranking 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 24

Measurement and Verification Measuring on routine basis is critical. Review regularly. 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 25

Designing the Control System Consider Design Conditions and Off-Design Conditions Design should Include Diagram, Sequence of Operation, Point List, Valve Schedule, and Damper Schedule Design should be Detailed, but not Manufacturer Specific Control System Design, Sequence, and Programming have more Impact on Hospital Energy Efficiency than System and Equipment Selections 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 27

Goal is Optimum Performance Include Fail-Safe Provisions Identify Inputs, Loop Statements, Table Statements, Logical Operators, Setpoints, Local Variables, and Outputs Developing the Sequence of Operation Consider Using a Flow Chart to Convey Design Intent Must be Very Detailed to Prevent Misunderstandings Lack of a Detailed Sequence is the Reason why most Buildings Fail to Achieve their Energy Efficiency Goals 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 28

AHU Supply Air Temperature Reset Control Loops Cooling Loopout /Chilled Water Control Valve is equal to the output of the following PI loop: Action Direct Input Supply Air Temperature Setpoint Cooling Setpoint Minimum Output 0 Maximum Output 100 Developing the Sequence of Operation Supply Air Temperature: The supply air temperature setpoint ( cold deck temperature ) is increased and decreased from the minimum to the maximum and vice versa according to the following logic: Input Request for more cooling from Air Terminals Output Supply Air Temperature Setpoint. Equal to the lower of comparison of Calculated Supply Air Temperature Setpoint (reset based on polling zones described in this section) and Dehumidification Override Supply Air Temperature Setpoint (section 9.c). Minimum SAT Setpoint (60F) Maximum SAT Setpoint (65F) Sampling Rate/Rate of Change: 1F/5 mins 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 29

Chilled Water System Issues Improper Chiller, Cooling Tower, and/or Pump Sequencing Differential Pressure Setpoint Reset Overridden Condenser Water Supply Temperature Reset Overridden (or not programmed). Low Chilled Water Temperature Difference (Low Delta T) 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 31

CV Primary/ Variable Flow Secondary Chilled Water System First developed by B&G in 1954. 2 Hydraulically Independent loops via Decoupler bypass pipe ( neutral bridge ). Primary pumps interlocked with each Chiller to provide design (constant) gpm. Secondary pumps are modulated to meet system DP requirement. 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 32

CV Primary/ Variable Flow Secondary Chilled Water System Perfect world Primary Loop GPM = Secondary Loop GPM. No flow in Decoupler pipe. In the real world this is seldom the case. 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 33

CV Primary/ Variable Flow Secondary Chilled Water System 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 34

CV Primary/ Variable Flow Secondary Chilled Water System KEY PERFORMANCE INDICATORS Secondary Loop Delta T. Low Delta T indicates excessive pumping. Chillers, AHU Coils are more efficient at higher delta T. System Operating DP. High system differential pressure can mask other problems. Higher DP = higher pumping horsepower. High DP s can adversely affect control valve/coil performance. Btu/h 500 GPM T For a given load, Flow and ΔT are inversely proportional. As GPM increases, ΔT drops. 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 35

CV Primary/ Variable Flow Secondary Chilled Water System Control Sequence Reset DP setpoint based on actual AHU demand (chilled water valve positions). Stage chillers based on tonnage but watch the temperature of water in decoupler and secondary loop Delta T for fault detection. Add secondary loop Delta T to dashboard. 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 36

Variable Primary Chilled Water Variable Flow through Chillers Only 1 Set of Pumps Pumps Sequenced to Maintain Delta P and Minimum Flow Bypass Valve Modulates to Maintain Minimum Flow Requires Electronic Flow Safeties Lower Capital Cost, Energy Cost, and Maintenance Cost 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 37

Condenser Water Relief Still many plants control tower water to single setpoint (80F aquastat) Chiller Efficiency improves with colder condenser water. 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 39

Lots of hours of operation even in South Texas

It s all about LIFT Condensing temperature minus the suction temperature Two ways to decrease Lift by adjusting DDC: Lower Condenser Water Temperature Raise Chilled Water Supply Temperature 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 41

Condenser Water Relief Implementation for Constant Volume Pumping Tower fan energy versus lower chiller kw Reset loop setpoint based on wet bulb and run the condenser loop as cold as possible 2 tower cells paired with 1 Chiller Be aware of lower limit. 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 42

Variable Volume Condenser Water System Valves Modulate to Maintain Proper Flow Flow at Design with Minimum Refrigerant Lift Override Chillers can Operate with Very Cold Condenser Water (eliminates transition issues with hydronic free cooling) Any Chiller with any Tower with any Pump Pumps Sequenced in a Best Efficiency Manner Towers Sequenced in Best Efficiency Manner 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 43

3.0 GPM per Ton Condenser Water Flow Rate 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 44

Air Handling Unit Issues Static Pressure Setpoint Reset Overridden Malfunctioning Control Valves Supply Air Temperature Setpoint Reset Overridden Failed Air Flow Measuring Stations Malfunctioning Dampers Weekly Schedules Overridden Simultaneous Heating and Cooling 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 46

Multiple Loop Temperature Control Loop 1 Loop 4 Loop 2 Loop 3 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 47

Multiple Loops 2022 Loop (0, Input, Output, Setpoint, P, I, D, Min, Max, Bias) 4 Setpoints 4 Sets of Proportional and Integral Gains Setpoints may Inadvertently Overlap Tuning is very Difficult Outputs will Overlap due to Hunting Simultaneous Heating and Cooling 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 48

Multiple Loops Mixed Air Preheat CHW Coils Time Mixed Air Temperature Mixed Air Setpoint Output Preheat Temperature Coil Leaving Preheat Setpoint Output Air Temperature Supply Supply Air Air Temperature Setpoint Output 3:00 55.3 55 51 55.3 50 0 40.7 47.5 48 24 3:05 48.0 55 76 57.6 50 24 41.6 48.1 48 27 3:10 57.7 55 42 57.7 50 0 42.0 48.9 48 26 3:15 60.5 55 33 60.5 50 0 42.2 48.3 48 30 3:20 54.9 55 51 54.9 50 0 40.9 47.2 48 23 3:25 47.5 55 79 54.7 50 18 41.0 47.6 48 23 3:30 58.3 55 39 58.3 50 0 41.8 48.4 48 28 3:35 62.0 55 29 62.0 50 0 42.3 48.7 48 33 3:40 54.1 55 55 54.1 50 0 41.4 48.2 48 21 3:45 48.5 55 75 52.9 50 11 41.1 47.6 48 20 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 49

Overlapping Setpoints Mixed Air Preheat CHW Coils Time Mixed Air Temperature Mixed Air Setpoint Output Preheat Temperature Coil Leaving Preheat Setpoint Output Air Temperature Supply Supply Air Air Temperature Setpoint Output 3:00 55.3 55 51 55.3 50 0 40.7 47.5 48 24 3:05 48.0 55 76 57.6 50 24 41.6 48.1 48 27 3:10 57.7 55 42 57.7 50 0 42.0 48.9 48 26 3:15 60.5 55 33 60.5 50 0 42.2 48.3 48 30 3:20 54.9 55 51 54.9 50 0 40.9 47.2 48 23 3:25 47.5 55 79 54.7 50 18 41.0 47.6 48 23 3:30 58.3 55 39 58.3 50 0 41.8 48.4 48 28 3:35 62.0 55 29 62.0 50 0 42.3 48.7 48 33 3:40 54.1 55 55 54.1 50 0 41.4 48.2 48 21 3:45 48.5 55 75 52.9 50 11 41.1 47.6 48 20 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 50 50

Simultaneous Heating and Cooling Mixed Air Preheat CHW Coils Time Mixed Air Temperature Mixed Air Setpoint Output Preheat Temperature Coil Leaving Preheat Setpoint Output Air Temperature Supply Supply Air Air Temperature Setpoint Output 3:00 55.3 55 51 55.3 50 0 40.7 47.5 48 24 3:05 48.0 55 76 57.6 50 24 41.6 48.1 48 27 3:10 57.7 55 42 57.7 50 0 42.0 48.9 48 26 3:15 60.5 55 33 60.5 50 0 42.2 48.3 48 30 3:20 54.9 55 51 54.9 50 0 40.9 47.2 48 23 3:25 47.5 55 79 54.7 50 18 41.0 47.6 48 23 3:30 58.3 55 39 58.3 50 0 41.8 48.4 48 28 3:35 62.0 55 29 62.0 50 0 42.3 48.7 48 33 3:40 54.1 55 55 54.1 50 0 41.4 48.2 48 21 3:45 48.5 55 75 52.9 50 11 41.1 47.6 48 20 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 51

What is the Problem? Mixed Air Preheat CHW Coils Time Mixed Air Temperature Mixed Air Setpoint Output Preheat Temperature Coil Leaving Preheat Setpoint Output Air Temperature Supply Supply Air Air Temperature Setpoint Output 3:00 55.3 55 51 55.3 50 0 40.7 47.5 48 24 3:05 48.0 55 76 57.6 50 24 41.6 48.1 48 27 3:10 57.7 55 42 57.7 50 0 42.0 48.9 48 26 3:15 60.5 55 33 60.5 50 0 42.2 48.3 48 30 3:20 54.9 55 51 54.9 50 0 40.9 47.2 48 23 3:25 47.5 55 79 54.7 50 18 41.0 47.6 48 23 3:30 58.3 55 39 58.3 50 0 41.8 48.4 48 28 3:35 62.0 55 29 62.0 50 0 42.3 48.7 48 33 3:40 54.1 55 55 54.1 50 0 41.4 48.2 48 21 3:45 48.5 55 75 52.9 50 11 41.1 47.6 48 20 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 52

Table Statement Output Single Loop Temperature Control 100 80 Preheat Valve 60 First Stage Economizer Cycle (Maximum OSA Damper) 40 20 Stage 1 Stage 2 Stage 3 Stage 4 Stage 5 Second Stage Economizer Cycle (Return Air and Relief Air Dampers) Secondary Chilled Water Valve 0 0 20 40 60 80 100 Primary Chilled Water Valve Supply Air Temperature Control Statement Output 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 53

Table Statement Output Single Loop Humidity Control 100 80 60 40 Disable Second Stage of Economizer Cycle (Opens Return and Closes Relief Dampers) Disable First Stage of Economizer Cycle (Closes Maximum OSA Damper) 20 Stage 1 Stage 2 Stage 3 Humidifier Steam Valve 0 0 20 40 60 80 100 Return Air Humidity Control Statement Output 12/5/2013 2012 American Society for Healthcare Engineering of the American Hospital Association 54

Adaptive Resets Reset Supply Air Temperature ( Cold Deck Reset ). Reset Duct Static Pressure Setpoint ASHRAE 90.1, Energy Code 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 55

Dedicated Outside Air AHU Pre-treat ventilation air. Ducted to outside air damper on individual AHUs. 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 56

Air-Side Economizer Cycles Air-Side Economizer Cycles often incorrectly programmed/configured and difficult to maintain. 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 57

3:00 3:05 3:10 3:15 3:20 3:25 3:30 3:35 3:40 3:45 Economizer Damper Control Loop not Tuned 90 80 70 60 50 40 30 20 10 0 Economizer Damper Output Mixed Air Setpoint Mixed Air Temperature 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 58

Air-Side Economizer Cycles on AHU s with Humidifiers ASHRAE Standard 90.1 Requires Hydronic Free Cooling if Humidification Dewpoint is > 35 deg. F (30% RH at 68 deg. F) Cooling Savings are more than Offset by Higher Humidification Costs Air-Side Economizer Cycles are Costly to Implement and Difficult to Maintain 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 59

Operating Room Challenges Surgeons/staff want 60F/50% rh Difficult if not impossible to achieve with typical chilled water system 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 60

Operating Room Challenges 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 61

Operating Room Challenges Desiccant Technology provides lower dewpoints. Dedicated OSA AHU with Type III passive dessicant wheel shown. 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 62

Operating Room Challenges Air change rates, pressure differentials difficult to optimize often are not reset based on occupancy. 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 63

Unoccupied/Occupied Reset for Operating Rooms Occupied 15 to 25 ACH Unoccupied 5 to 8 ACH DP 0.01 w.g.

Air Terminal Issues Failed Averaging Velocity Sensors Malfunctioning Terminal Dampers Malfunctioning Heating Water Control Valves Insufficient Air Flow to Accommodate Space Sensible Cooling Load Incorrect Air Flow Setpoints Deadband too Small Thermostat Range not Restricted Weekly Schedules Overridden Occupancy Sensors Overridden Failed Points Simultaneous Heating and Cooling 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 66

VAV Air Terminal with Heating 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 67

VAV Air Terminal with Heating Minimizing Reheat Best Practice: Modulate HW Valve to a Discharge Setpoint and Reset the Setpoint from Minimum up to Maximum before Increasing Air Flow. 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 68

VAV Air Terminal Troubleshooting Failed Averaging Velocity Sensors Malfunctioning Terminal Dampers Malfunctioning Heating Water Control Valves Insufficient Air Flow to Accommodate Space Sensible Cooling Load Don t apply a system wide correction to a zone level problem. 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 69

You can t manage what you don t measure. Closing Thoughts The code is the key. Get it right and good things happen. Don t use a sledge hammer to drive a finish nail. 12/5/2013 HAAHE/TAFHM Facility Manager Basic Training 70

Thank You! Questions? The only constant is change. - Heraclitus It is not the strongest of the species that survives, nor the most intelligent that survives. It is the one that is the most adaptable to change. Charles Darwin 12/5/201 2012 American Society for Healthcare Engineering of the American Hospital Association 71