Natick Readiness Center Report-6.7.17.pdf

Part 1: Energy Assessment Part 2: Capital Investment and Maintenance Planning Part 3: Alternative Energy Feasibility Study

Massachusetts National Guard Readiness Center, Natick, MA

May 2017

Prepared for:

Massachusetts National Guard 149 Speen Street, Natick, MA 01760

Prepared by:

Guardian Energy Management Solutions™ 420 Northboro Rd. Central Marlborough, MA 01752

Stop Wasting Energy. Start Saving Money.™

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Massachusetts Army and Air Force National Guard Executive Summary Natick Readiness Center 149 Speen Street, Natick, MA May 2017

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Table of Contents Section Page

1. EXECUTIVE SUMMARY

2. PROJECT CONTACT INFORMATION

PART 1 - ENERGY ASSESSMENT

3. FACILITY DESCRIPTION

Building Envelope / Physical Structure

Occupancy Schedule

Lighting Systems

HVAC Systems

HVAC Controls

Domestic Cold and Hot Water

Other Systems

4. UTILITIES

Electricity

Natural Gas

Diesel

Water

Energy Use and Costs by Percentage

5. ENERGY CONSERVATION MEASURES

ECM 1 Re-pipe Heat Pump

ECM 2 EMS Improvements

ECM 3 Lighting Upgrades

ECM 4 Vendor misers

6. OPERATION AND MAINTENANCE

Maintenance Practices

O&M Recommendations

O&Ms for Energy Conservation

O&Ms for Maintenance

APPENDIX A: UTILITY RATES AND SAMPLE BILLS

APPENDIX B: EQUIPMENT LIST

APPENDIX C: LIGHTING ROOM BY ROOM

PART 2: CAPITAL INVESTMENT AND MAINTENANCE PLANNING

PART 3: ALTERNATIVE ENERGY FEASIBILITY STUDY

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1. EXECUTIVE SUMMARY

The Massachusetts Army and Air Force National Guard solicited bids to perform an “Energy Analysis” of their Readiness Center in Natick, MA. This Energy Analysis has three parts:

Part 1: Energy Assessment – a review of energy usage of facility energy using systems with recommendations on how to save energy.

Part 2: Capital Investment and Maintenance Planning – a review of existing conditions with respect to existing maintenance practices and future maintenance requirements and costs, as well as the costs of not doing recommended maintenance.

Part 3: Alternative Energy Feasibility Study – A review of the potential use of various renewable systems and co-generation.

Part 1: Energy Assessment

It is common in this type of energy audit to perform benchmarking which enables one to compare the energy use of this facility to another similar facility. Unfortunately there are no available databases with which to compare this particular facility to. In any case the benchmarking data is shown in Table 1.1.

Table 1.1: Annual Bench Marking Data

Source Energy Cost Use kBtu kBtu/ft² % of Annual Avg Unit $/ft² % of

Electricity (kWh) 305,550 1,042,842 22.41 40% $61,721 $0.202 $1.33 81% Natural Gas(ccf) 15,481 1,548,139 33.26 60% $14,243 $0.920 $0.31 19%

Totals: 2,590,981 55.67 100% $75,964 $1.63 100%

Note: Facility area = 46,540 ft2

A number of Energy Conservation Measures (ECMs) were found that if implemented could save utility costs shown in Table 1.2.

Table 1.2 Building Operating Costs -- Financial Highlights

Utility Current Projected Projected Estimated

Annual Energy Annual Energy Savings Installed Simple Costs Costs % Cost Costs Payback Return

Electric $61,721 $48,022 22% $13,699 N. Gas $14,243 $11,912 16% $2,331

Total $75,964 $59,934 21% $16,030 $79,465 5.0 20%

Notes Based on current usage of 305,550 kWh and 15,481 Therms. If all recommendations are implemented projected energy use would be reduced to: 237,731 kWh and 12,948 Therms.

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In addition to energy cost savings, reducing facility energy usage will also provide environmental benefits that include reducing greenhouse gas emissions (GHG). The information in this evaluation can be used by the MA National Guard to develop a GHG Inventory Plan in accordance with the EPA’s Climate Leadership Program.

Table 1.3 - Building Operating Costs Reduced Energy & Power Plant Emissions (note)

Carbon Dioxide (1.37 lbs/kWh, 11.76 lbs/Therm) 194,708 lbs/year Sulfur Oxides (0.0035 lbs/kWh, 0.0001 lbs/Therm) 345 lbs/year Nitrous Oxides (0.001 lbs/kWh, 0.0098 lbs/Therm) 148 lbs/year

Note: Based on 67,819 kWh and, 2,534 therms of natural gas savings.

Emission unit source: U.S. EPA eGrid and U.S. EPA Office of Air Quality Planning & Standards

The opportunities for energy savings that can be considered for implementation are summarized in Table 1.4 and described later in Section 5 of the Energy Assessment part of the report.

Table 1.4 – Building Operating Costs Summary of Energy Saving Opportunities

Energy Efficiency Measure Estimated Savings Cost

Estimate

Simple Payback

(years) (3) kWh Therms $

1 Re-Pipe Heat Pump (1) 9,595 0 1,938 $14,000 7.2 / 6.2 2 EMS Improvements (2) 30,662 2,534 8,525 $25,000 2.9 / 2.9 3 Lighting Upgrades 25,950 0 5,242 $40,165 7.7 / 5 4 Vendor miser 1,612 0 326 $300 0.9 / 0.6

Totals 67,819 2,534 $16,030 $79,465 5.0 / 4.0

Notes 1: Re-piping the heat pump is needed more for maintenance and equipment life issues than energy savings. A full write up of the issues are in Section 5 and 6.

2: EMS (Energy Management System) Improvements includes the following:

2.1 Make EMS Useful

2.2 Deepen Un-occupied set back

2.3 Unoccupied closing of OA damper

2.4 Optimum start

2.5 DCV in Assembly Hall and Offices

2.6 Use only passive heat at night

3: Simple paybacks, if a single number, the ECM does not qualify for utility incentives, if two numbers the first is without incentives and the second with utility incentives.

Project Contact Information follows this Executive Summary. Part 1 of the report is then presented and includes the following sections:

• Facility Description

• Review of the Current Building Energy Consumption

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• Energy Conservation Measures

• Operation and Maintenance and O&M Measures

• Appendix A: Utility Rates and Sample Bills

• Appendix B: Equipment List

• Appendix C: Lighting Audit

Part 2: Capital Investment and Maintenance Planning

Part 2 is located at the end of this report after the Part 1 Appendices. It includes a general discussion of reactive versus predictive maintenance and how to set up a predictive maintenance program and the record keeping needed to do so. Part 2’s Appendix includes a Maintenance Schedule & Estimated Cost of Preventive Maintenance plan, which summarizes the financial impact of performing maintenance on major building systems according to best practices.

Experience shows that without a thorough, documented preventive maintenance program the cost of reactive repairs is estimated to be 60% of the maintenance budget. With a thorough, documented, preventive maintenance program the ratio can be shifted to 60% preventive maintenance and 40% reactive maintenance.

The major deferred maintenance problem we found at the Natick Readiness Center is the lack of an electrical equipment maintenance program. The lack of an Electrical Preventive Maintenance program increases the risk of unplanned outages which have significant costs. Experience shows that on average you may expect a minimum of six hours of business interruption caused by even a small electrical failure in the distribution system.

Annual maintenance costs are currently minimal since most equipment is relatively new. As equipment ages breakdowns will occur more often and reactive maintenance costs will significantly rise. By implementing a preventative maintenance plan these reactive maintenance costs will be reduced by an estimated 20%.

According to Building Equipment Maintenance 2nd ed. by Sheldon Fuchs, PE. "A timely PM inspection program usually uncovers problems before they become serious enough to cause equipment failure. As a result, routine adjustments and minor repairs take the place of failure."

He adds that a successful PM program reduces total maintenance costs by about 15%.

Table 2.1 summarizes the financial impact of performing preventative maintenance on all major building equipment according to manufactures’ recommendations.

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Table 2.1 -- Estimated Annual Costs of Preventative Maintenance

Annual cost of HVAC Preventative Maintenance $11,380 Annual estimated repairs @ 40% of PM Cost $4,552

Annual Preventative Maintenance Program costs $15,932

Costs of not doing preventative maintenance Reactive maintenance is waiting for equipment to fail before addressing the problem by either replacing the failed equipment altogether or buying parts and fixing the failed equipment.

Reactive maintenance, by definition, causes a disruption of service and shortens the life of equipment.

The mean expected life time of equipment is provided in a table in Part 2. With a PM program equipment should last about 20% longer. Without a PM program, expected life is reduced by an estimated 20%. Most equipment is quite expensive. Extending life of equipment is usually worthwhile plus implementing a successful PM program reduces unplanned work emergency situations and overtime.

Part 3: Alternative Energy Feasibility Study

In this report, Part 3 follows Part 2’s appendix. The various common alternative systems were evaluated with a broad brush analysis. The reason alternatives are gaining acceptance in the market place is because of tax incentives and renewable energy credits (RECs) which brings down the cost of installation considerably. Massachusetts is currently in the process of changing its RECs program into its SMART (Solar Massachusetts Renewable Target) program. MA National Guard may be eligible for these credits. Table 3.1 summarizes likely economics of the reviewed systems without SMART program incentives. It is doubtful that these SMART incentives will alter the economics enough to make these alternatives attractive.

Table 3.1 - Alternative Energy Feasibility Study Summary of Alternative Systems

Alternative Energy System Estimated Savings Cost

Estimate

Simple Payback (years) kWh Therms $

1 Photovoltaic System 84,238 0 $17,016 $274,769 16 2 Solar Thermal System -663 611 $428 $28,753 67 3 Geothermal System -10,443 1,222 -$985 $18,000 -18 4 Cogeneration System 645,000 -57,393 $59,428 $240,000 4.0 5 Wind System not enough resource to consider

Note 1: For cogeneration a maintenance contract of $18,060 was subtracted from annual cost savings.

For all other systems annual operating costs does not include maintenance.

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2. PROJECT CONTACT INFORMATION

Project Location:

Massachusetts National Guard Natick Readiness Center 149 Speen Street Natick, MA 01760

Project Manager:

John Kent, Construction Coordinator, Construction and Facility Management Office 339-202-3973 john.j.kent.mil@mail.mil

Site Contact:

Stephen Raymond, Building and Utilities Supervisor 508-509-5745 stephen.raymond@state.ma.us

Guardian Energy Management Solutions:

Stephen Brown, Director of Construction 774-258-1852 sbrown@guardian-energy.com

Steven Kinz, Project Manager 774-258-8554 stevek@guardian-energy.com

Energy Auditor:

Jim Guertin, PE, CEM 617-471-3454 jim@UTSee.com

Massachusetts Army and Air Force National Guard Part 1 – Energy Assessment

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PART 1 - ENERGY ASSESSMENT

3. FACILITY DESCRIPTION

The Natick Readiness Center has two buildings on its property. The main building was built in 2013 and is 46,540 square feet in area. The other building on the property is a large storage garage that is not included in this study.

Readiness Centers are the modern version of what used to be called Armories, The Natick Readiness Center has two-stories without a basement. The first floor houses offices, storage areas, an entrance lobby, common corridors, I/T room, weapons vault, commercial-type kitchen, work out room, a large locker area, men’s and women’s locker rooms with toilets and showers, hydraulic elevator, stairs, mechanical and electrical rooms and a large 1 story high ceilinged Assembly Hall,. The second floor has individual and group offices, classrooms, library, men’s and women’s rooms, storage and janitor’s closets.

A number of HVAC units are located on the roof as are a number of solar tubes that bring sunlight into the second floor group office areas.

Building Envelope / Physical Structure General Construction The structural system for the building includes a poured concrete foundation wall and piers on spread footing, a poured-in-place ground floor slab, a steel super-structure supporting a second level poured-in-place slab and the metal roof deck. There are steel trusses supporting the raised roof of the Assembly Hall.

The masonry exterior facade has aluminum windows. The roof has a thermoplastic membrane over rigid board insulation. Interior wall construction is primarily of CMU or GWB on metal studs.

The Assembly Hall has two operable panel partition walls. Building systems include heating, cooling and ventilation, electrical, plumbing and fire-protection, security and tele-communications.

Walls and Roof The building exterior walls have 4-inch face brick with cast stone masonry units (CSMU) in strips at multiple levels. The exterior veneer is followed by 1-3/4” air space, 3” foam board insulation, ½” fiberglass board, and 6” metal studs covered with 5/8” gypsum board (GWB) or 8-inch CMU instead of the GWB. The roof from the inside out has a metal deck covered with up to 8-inch foam board tapered to provide flow to roof drains and topped with an adhered

Guardian Energy Management Solutions, Marlborough, MA Page 9 of 40 thermoplastic membrane. As with most membrane roofs, keeping debris clear, use of wear pads, and the consistent inspection will add life to this roof.

Roof drains are tied into a storm water system. The outside masonry walls have an effective system of weep openings around the perimeter and at the base of the wall. There is no visible damage around the walls and lintel supports of windows and doors.

Interior walls have either CMU or GWB surfaces.

Windows and Doors The windows are an extruded aluminum of high quality construction with an energy designed thermal pane. There were no visible sign of thermal pain failure or excessive air leakage from window frames. Doors also were of good energy design (well weather stripped) and no excessive wear was apparent during the walk through. The overhead doors showed very little abuse or deterioration. Bottom seals were tight to slab. As with all mechanical moving parts (especially overhead doors) and weather stripping, a regular program should be in place to maintain and service the doors.

Occupancy Schedule The building is occupied five days a week from about 6 AM to 5 PM. The building is also used by Natick community groups for meetings a couple of times a month that occasionally last until about9 PM.

Weekends the buildings are closed except that once a month, on drill weekends, the building is opened from about 6 AM to 5 PM and on occasion for community groups. Weekday staff occupancy is about 20 to 50 people. Community groups can have 5 to 50 or more. On drill weekends there can be many more guardsmen.

The HVAC system is currently scheduled to maintain all areas to occupied temperatures from 4 AM to 7 PM during weekdays and from 7 AM to 7 PM on weekends.

Lighting Systems T-5 fluorescent fixtures with electronic ballasts, compact fluorescent and LED lights provide interior illumination. Present lighting is controlled manually and in some areas by occupancy sensors. There is also a daylighting control for areas with solar tubes (skylights). Building exterior lighting is provided by LED wall-mounted fixtures. Parking lot lighting is by 254-Watt and 129-Watt LED, pole-mounted fixtures. Exterior lighting is controlled by an astronomical time clock.

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HVAC Systems There are many different HVAC systems in the building. Table 1.5 lists the different types of equipment serving the Readiness Center. A full listing with connected demand and estimated operating times, connected demand and annual kWh is provided in Part 1 - Appendix B.

Table 1.5 -- Readiness Center HVAC Equipment List

Equipment Type Symbol Qty Both Heating and Cooling

Air Handler AHU 1 Energy Recovery Unit ERU 3 Valance Unit VU 51 Chilled / Hot Water Pump P1, P2 2 Destratifying Fan Fan 2 Exhaust Fan EF 13

Heating Only Cabinet Heater CUH 7 Electric Unit Heater EUH 2 Kitchen Exhaust Fan KEF 1 Kitchen Makeup Air Unit MAU 1 Unit Heater UH 6 Boiler pump BP 2 Condensing boiler B 2

Cooling Only Condenser Water Pump P-3, P4 2 Cooling tower CT 2 Ductless Split System ACU 3 Heat Pump (1) HP 2

TOTAL 102 102

Note (1): The heat pump was supposed to provide heating and cooling but it was incorrectly installed and only provides cooling.

The 1st floor mechanical room houses the boilers, heat pumps, domestic hot water systems and pumps. The building is LEED certified and as a result cannot be heated and air conditioned at the same time by the central system. The central system has boilers and heat pumps which make hot or chilled water to circulate around the building.

Boilers

The two boilers are high efficiency condensing boilers each having its own primary pump. The building distribution system has a set of secondary duplex pumps. Boiler heated water flows in the mechanical room primary loop that shares a leg with the secondary system. One secondary pump circulates hot water to all terminal systems (AHU, ERUs, VUs, UHs, CUHs and MAU).

At the terminal systems local valves open or close to allow more or less hot water into its coil in

Guardian Energy Management Solutions, Marlborough, MA Page 11 of 40 order to satisfy local thermostats. This is straight forward. What is different about this system is the incorporation of valance units (discussed below).

Heat Pump

A duel Multistack heat pump, model MS050XN4H2R0AAC-410A, provides chilled water to the secondary loop in the summer when the boiler is shut down. The unit was supposed to be able to also make hot water, but it was not plumbed correctly. The unit has separate heating and cooling sides with two 25 ton scroll compressors on each side.

It should have been piped in primary/secondary configuration but is now in a variable flow primary configuration with the building’s secondary pumps directly primary pumps. The problem is that proper flow is never established through the heat pumps evaporator barrel. As a result, the evaporator runs too cold with poor efficiency, and when the building calls for more cooling the second compressor kicks in and the unit trips out on low pressure/temperature.

Manual reset is then needed.

Cooling Tower

The heat pump’s condenser barrel is piped to a closed circuit cooling tower on the roof and the line filled with a glycol solution. A set of duplex pumps sends the fluid to the tower. The tower has three modes of operation, depending on the cooling load and weather. First, the fluid is cooled by convection from outside air; Second, the tower’s basin water pump comes on and sprays water over the closed circuit piping. And third, which is the main operating mode, the basin water pump is on and the tower fans (there are 2 of them) come on.

In the winter the basin is drained and the glycol filled line is heat traced to prevent freezing.

Valance Units

A valance unit is basically a few lengths of fin-tube radiators mounted high on (mostly) exterior wall(s) of the room being heated/cooled. The VU has a metal shroud around its bottom, to capture condensate when it is used in the cooling mode. The buoyancy of the heated/cooled air causes it to rise/sink and as it does it contacts cooler/warmer surfaces and drifts down (especially when next to windows) a natural circulation occurs. The areas with VUs are also fed air from energy recovery units (ERUs). The flow from the ERUs fortifies the circulating flow pattern.

Energy Recovery Units

The ERUs have built-in energy recovery wheels that exchange heat between exhaust and incoming ventilation air. There is also one heat exchange coil in each ERU that adds heat or cooling (incapable of doing both) into the room supply air stream if needed.

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Air Handler Unit

The Assembly Hall is heated/cooled by an air handler unit (AHU-1). The Assembly Room has a ~28 foot ceiling and near the ceiling on the east side is a row of operable louvers. In the summer the louvers can be opened to let the hot inside out and fresh air in. When the louvers are opened the AHU is disabled. To help with air movement the room has ceiling mounted two “Big Ass” fans with 16 foot blades that circulate air. The fans have a speed control so staff can slow down the fans so the “wind’ doesn’t clear desks of paper.

Make-up Air Unit

The kitchen is a large commercial kitchen with an array of gas-fired cooking systems: cook top, roasting oven, convection oven, fryolator, grill, etc. Drill weekends are essentially the only time the kitchen is used. The cooking area is under a large hood that exhausts cooking vapors and smoke. A lot of air is exhausted from the hood and a MAU brings in and conditions replacement fresh air. The exhaust fan and MAU are only used when the kitchen is being used mostly, if not always on drill weekends. The kitchen also has a dishwashing area with its own exhaust fan.

Ductless Split Systems

Since there is no mechanical cooling available from the main system in the winter, areas that need year round cooling have their own split systems providing cooling in the winter. The areas needing year round cooling are ones with lots of electronics; IT, communications, etc.

Unit and Cabinet Heaters

A few locations are heated with unit and cabinet heaters such as the lobby, storage rooms, etc.

Electric rooms are heated with electric unit heaters and so is the emergency generator enclosure that is located on the south side of the building.

HVAC Controls The EMS coordinates the control of HVAC equipment and is used to change set points and monitor space and equipment conditions. Much of the HVAC equipment are self-contained/controlled but report data to the EMS for trending. Using split systems as examples:

all have local thermostats that control how often their compressors come on to provide cooling that will satisfy their thermostats. Further, the condenser unit fans come on as needed to maintain the compressor head pressure at its set point. This “independent” control is true for hot/chilled water coil valves of the AHU, ERUs, UHs, CUHs, MAU, and others. EUHs turn on and off to satisfy their local thermostats.

All the major pumps and fans in the HVAC system are on VFDs. For pumps, as individual unit coil valves open and close, distribution pressure changes. The pump VFDs are set to maintain a constant pressure differential and speed up or slow down as pressures drop or rise, respectively.

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Similarly with fans, as air dampers open or close distribution system pressure changes. The VFDs speed up or slow down the fans accordingly. Also static pressure reset is employed by the EMS. The system’s static pressure set point is allowed to be reduced (by slowing down the fan) while all thermostats are monitored. Fan speed continues to get incrementally slower over time until a thermostat becomes unsatisfied and the fan speed is then incrementally increased. This incremental adjustment of fan speed, up and down, is continually done so that fan speed is minimized. Fan speed is related to the change in speed raise to the cube so a lot of savings can be obtained.

Boilers are controlled to maintain a hot water temperature set point. If one boiler cannot meet the set point the second boiler comes on. The hot water set point is adjustable from 180ºF to 140ºF. At 10ºF outside air temperature (OAT) and below, hot water temperature is controlled to 180ºF. Above 60ºF OAT hot water temperature is controlled to 120ºF. In between those two OATs hot water temperature varies linearly.

EMSs typically have advanced energy saving features, some of which were discussed above, that include:

Table 1.6 -- EMS Advanced Energy Saving Functions

Function Description

1 Reporting and Trending Recording data for troubleshooting and verifying that systems and energy features are operating properly

2 Un-Occupied set back Lowering building temps during un-occupied periods 3 Control of Exhaust Fans Turn off when not needed 4 Optimum Start and Stop Heating/Cooling the building just-in-time as 1st occupants arrives

5 Demand Controlled Ventilation Uses measured CO2 as a proxy for occupancy and adjusts ventilation rates as required

6 Static Pressure Reset Reducing AHU fan speeds to as low as possible while still meeting temp set points

7 Hot Water Reset Adjusting heating hot water temp to outside air temp.

8 Chilled Water Reset Adjusting chilled water temp to outside air temp.

9 Dual Enthalpy Economizer Comparing OA and return air and choosing that which is the lowest cost to cool

The EMS has many of these advanced features, but the system is unfriendly in that it is not clear which functions it does have or if they are working properly.

Reporting and Trending

Number 1 in Table 1.6 (trending and reporting) was available for many (not all) points that were being recorded every 15 minutes all the time. A point is an input or output to/from the EMS.

For example VFD speed, hot water temperatures, water and air flow rates, outside and inside air temperatures, CO2 levels, air and valve positions, etc. are all points.

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The building operator can track the history or trends of these points. For example if in certain spaces occupants are complaining, thru EMS trends it can be verified that there is a problem and possibly give the operator an idea what is going wrong (if anything).

Trending is an excellent way to document that all the advanced features of the EMS are working properly and saving energy as they should. However, what plots should the manager make to verify correct operation? The EMS is not set up to be helpful in that regard. A set number of plots should be programmed so that a quick glance will tell the manager that energy saving features are working as they should or document that they are not working.

Un-Occupied Set Back

Figure 1.1 shows the return air temperature from the Assembly Hall served by AHU-1. Return air temperature is essentially space temperature and the plot shows that temperature rise to occupied settings by 4 AM and start drifting down at 7 PM. On weekends the temperature starts rising at 8 AM and then drop again around 4 PM. The difference between un-occupied and occupied temperatures is about 5º to 7ºF on weekdays and considerably more on weekends. This shows that un-occupied set back is programmed in the EMS. Other areas also demonstrated working un-occupied setbacks, however, the setbacks were much smaller than could be handled by the building.

Figure 1.1 -- Demonstration of Un-Occupied set backs

In the summer air conditioning is shut off in un-occupied times.

Control of Exhaust Fans

We were not able to download any exhaust fan data, but it is believed they are shut off during un-occupied times. If they are not, they should be.

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Optimum Start and Stop

An essential feature of this function is to shut outside air dampers tightly so that when the building starts up in the morning the heating system only heats the building and not outside air.

Figure 1.2 shows that optimum start is not being employed by the EMS (although we did find optimum start settings in the EMS). In the figure the outside air damper is opened all hours of the day (the blue diamonds). During ALL un-occupied times the OA damper should always be tightly shut. If they are shut tight on startup the building warms more quickly instead of taking a few hours to come to temperature as shown in the figure.

With the optimum start function the EMS calculates how long it takes the building to warm up in the morning from un-occupied settings, with the OA dampers closed. The EMS calculates the building time constant which is given as “minutes warm up time per ºF difference between inside temperature setting and outside air temperature”. For an example the time constant is say 3 minutes per 1ºF. So if the inside occupied set point is 70ºF and the outside air temperature is 20ºF, the EMS knows to start the building’s heating system 150 minutes [=3*(70-20)] before the first occupants are scheduled for arrival. Obviously the more mild it is outside the shorter it takes to warm up the building. Having a constant start time before 4 AM, is shown on the plot will make sure the building is warmed up by 7 AM even on the coldest days; however, on milder days extra hours are spent at occupied settings when not needed, thus wasting energy. And with the OA damper open during startup a lot of energy is wasted and the building takes more energy to come to occupied set points.

Figure 1.2 -- Demonstration of Un-Occupied set backs for AHU-1

Demand Controlled Ventilation (DCV)

Heating and cooling outside ventilation air is expensive. DCV uses readings from CO2 sensors to adjust the volume of OA taken in. People breath out CO2, fewer people mean less CO2, more people means higher concentration of CO2. Using DCV the EMS should keep CO2 concentrations below about 1,000 ppm (parts per million). Figure 1.3 is the same as Figure 1.2

Guardian Energy Management Solutions, Marlborough, MA Page 16 of 40 except that the 15-minute OA damper data is missing and CO2 levels are included. In the figure CO2 levels get to just over 500 ppm and the OA damper “% open” hovers around 40%. If DCV were functioning CO2 levels would be controlled to near 1,000 ppm, and the OA damper position would vary and be considerable lower than 40%. The best places to use DCV are in spaces where occupancy varies greatly, like the Assembly Hall and class/training rooms. The Assembly Hall already has CO2 sensors and DCV should be utilized there as well as in the class rooms.

Figure 1.3 -- Demonstration of DCV not being used in AHU-1

Static Pressure Reset

Static pressure in a systems duct work varies with time as the system dampers open and close and fan speeds vary as a result. System fans have VFDs to adjust fan speeds to maintain a set static pressure. Static pressure reset allows the system static pressure set point to lower. The lower the system static pressure the lower the fan speed thus savings fan energy. Figure 1.4 shows how AHU-1’s static pressure varies with its supply fan speed. Fan speed will normally vary to maintain a set static pressure. With static pressure reset engaged, static pressure will relax a bit and fans will slow more than they otherwise would.

Figure 1.4 -- Demonstration of DCV not being used in AHU-1

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The orange straight line in Figure 1.4 is a linear regression line which shows system static pressure rises slightly as the speed drops. If static pressure reset were engaged the static pressure would reduce as fan speeds lower.

Hot Water Reset

From the trended data plotted in Figure 1.5 it was confirmed that hot water reset was essentially working properly.

Figure 1.5 -- Demonstration of Hot Water Reset Working

Chilled Water Reset

Similar to hot water reset, chilled water temperature should get warmer as the cooling load (outside air temperature) falls. Figure 1.6 shows that, in general this does not happen. The higher the chilled water temperature the less work the chiller needs to do thus savings energy.

Figure 1.6 -- Demonstration of Chilled Water Reset NOT Working

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Dual Enthalpy Economizer

The economizer function uses outside air to cool a building instead of mechanical refrigeration.

Outside air conditions need to be right so that the building’s cooling load is not increased due to bringing in outside air that needs to be conditioned. Enthalpy is a property of air that measures air temperature and its moisture content. A dual enthalpy economizer compares the enthalpy of air in a space to the enthalpy of outside air. Whatever has the lowest enthalpy is the air stream that is favored since it will take the least energy to cool. Using dual enthalpy economizing maximizes the benefit of “free” outside air building cooling. The trend data from last summer indicates that dual enthalpy economizer is operating.

Domestic Cold and Hot Water Hot water that comes out of all faucets is termed domestic hot water or DHW. DHW is heated in the main mechanical room by two 250 gallon gas-fired storage tank water heaters (PVI, Power VT, model 560P 250A-PV) capable of delivering ~375 MBH to the water at full fire. One unit is meant for the kitchen the other for the rest of the building; however they are piped in parallel with both tanks serving the whole building including the kitchen. The DHW heaters are power vented and rated at a 94% combustion efficiency at full fire. The tank heater control panels were indicating hot water temperatures of 153ºF and 143ºF. Potable hot water is circulated around the facility in two loops by 1/6 HP pumps. These small pumps are controlled by aquastats set at ~120ºF so when circulating water comes back from the building higher than 120ºF the pumps shut off.

Cold and hot water is used in all sinks and showers in the building. Toilets and urinals make up the rest of the use.

Other Systems Office areas have computers and IT has a small server room. There are other common office systems in the building including: audio/visual equipment, copy machines, etc. The kitchen has a one-door and a two-door refrigerator and one one-door freezer. The two-door refrigerator is used during drill weekends. To prepare for drill weekends quantities of frozen food are placed in the two-door refrigerator a day or two before the weekend and allowed to thaw. The two-door refrigerator is emptied at the end of the weekend, except for condiments and miscellaneous items. The two-door unit has an anti-condensation heater for its door frames which is left on all the time, even though it is not needed in the winter.

The freezer is turned on only for drill weekends and is otherwise emptied and shut off. The one-door refrigerator is used on drill weekends but is also used daily to hold guardsmen lunches and drinks.

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The building has radio and other types of communication equipment and miscellaneous uses that draw the rest of the electrical demand seen on the monthly utility bills.

A 350 KW Caterpillar Emergency Generator is located in an enclosure on the south side of the building. The enclosure has a 4.2 kW space heater and the generator has a 3.0 kW block heater;

both are not needed.

4. UTILITIES

Electricity Eversource supplies electricity and natural gas to the site. The Readiness Center purchases electricity thru meter # 5112252, account # 2881 393 0014, under rate code B7-NEMA LG General TOU. The bills are delivered to MA National Guard’s Joint Force Head Quarters at Hanscom AFB. The Readiness Center’s building operator does not see the bills so has no way of knowing or understanding how the building uses energy. This is not a good practice.

We were provided electrical billing data for most of fiscal years 2015 and 2016. Table 1.7 shows the average of these monthly values. The Center gets billed for electric demand kVA, which is kW divided by power factor. Power factor at the site varies monthly and averaged 90% for most of last year.

The marginal cost of energy is the cost of the last unit purchased, thus the cost of the first unit saved. Calculating cost savings from conservation efforts uses this marginal cost. Combining the delivery and commodity costs and multiplying by Eversource’s B7 rate variables, the average blended marginal cost of electricity is $0.202 / kWh. Blended means the kW costs are included in the cost per kWh number.

Table 1.7 Average Electrical Consumption for October 2014 thru September 2016 Month KWH Cost

Jan 33,444 $6,251 Feb 30,084 $5,724 Mar 22,584 $4,261 Apr 26,124 $5,166 May 24,924 $4,499 Jun 28,272 $6,931 Jul 21,519 $5,215

Aug 28,312 $6,861 Sep 16,388 $3,320 Oct 14,787 $2,729 Nov 30,048 $5,488 Dec 29,064 $5,270

TOTAL 305,550 $61,713

Note: Available electric bills from the JFHQ do not list kW or kVA although Eversource bills on KVA

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This same data is plotted in Figure 1.7.

Figure 1.7 Average Electrical Consumption for November 2014 thru June 2016

For this site we were able to obtain 5 minute interval data for the site from Eversource.

Although they did not have a full years woth of interval data they did have it for June 2016 through February 2017. This interval data in kWh was converted to 15-minute intevals and plotted below in Figure 1.8.

From the plot start times can be seen at the bottom where it changes from dark blue to green or yellow. At the top the abrupt change is when the HVAC systems are shut off (around 8 PM).

There are times when demand is essentially constant from midnight to midnight; this is believed to be monthly drill weekends. In July and August consumption is at its highest. It is interesting to see that in the evening between about 6 PM to 8 PM in June and the first part of July, shown circled in white (and on most non drill weekends) power draw is at its lowest because the color is purple instead of dark blue. It is not clear why most evenings do not draw the same low values.

And further, why doesn’t that purple area extend to the next morning? We do not know but it is likely that with a few “tweeks” of the EMS it likely could.

Figure 1.8 Interval Data showing Electric Consumption

Interval Data Missing

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Figure 1.9 Interval Data showing Peak and Average Weekly Electrical Consumption

Figure 1.9 illustrates how air conditioning consumes electricity. When the heat pump piping problems are fixed and with DCV employed these values should come down considerably.

Figure 1.10 Interval Data showing Peak and Average Daily Electric Consumption

Figure 1.10 shows that morning start up is pushed to very early in the morning. Making sure that all outside air dampers are shut tight at night and optimum start-up is used, will bring early morning consumption between 4 AM and6 AM way down where it should be. Then the morning “wake-up” spike can be move closer to 6 AM, thus saving a considerable amount of energy.

Figure 1.11 shows that just a very small percentage of the time the building draws above 80 KW.

If that maximum power draw can be lowered down to 80 kW $750 would be saved during those

Guardian Energy Management Solutions, Marlborough, MA Page 22 of 40 months when the peak occurs.

Figure 1.11 % of Time Drawing Specific Levels of Power

Natural Gas The Readiness Center also purchases natural gas through Eversource. The account number is 2892 431 0023, meter number is D000593 and it is billed under rate code 27-Federal Heating.

Again the bills get delivered to MA National Guard’s Joint Force Head Quarters at Hanscom AFB and the Readiness Center building operator has no way of knowing or understanding how the Readiness Center is doing energy-wise, since they never see the bills.

Gas bill data was provided for fiscal years 2015 and 2016. Table 1.8 shows the average of these monthly values.

The marginal cost of natural gas for the most recent annual billing (Oct 2015 – Sep 2016) was

$1.141 / CCF.

Table 1.8 Average Natural Gas Consumption for October 2014 thru September 2016

Month Therms Cost Jan 3,053 $2,843 Feb 2,624 $2,407 Mar 2,183 $2,082 Apr 1,248 $1,069 May 724 $572 Jun 118 $92 Jul 135 $131 Aug 88 $77 Sep 124 $95 Oct 456 $294 Nov 2,194 $2,107 Dec 2,534 $2,442

TOTALS 15,481 $14,211

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The data in Table 1.8 is plotted in Figure 1.12.

Figure 1.12 Average Natural Gas Consumption for October 2014 thru June 2016

Diesel The emergency generator is diesel and runs on diesel fuel. The generator sits on a 1,500 gallon storage tank. In the past two years there was only one purchase of diesel which occurred in January 2016. 356 gallons were purchased for $515 for a unit cost of $1.45 / gallon.

Water Water and sewer are provided and billed by the Town of Natick, MA under account # 1060600.

The reviewed billing data is shown in Table 1.9. The bills provided only had costs listed, we had to back calculate the gallons used.

Table 1.9 Water Consumption and Charges for Nov ‘14 – Aug ‘16

WATER SEWER

DATE Gallons Cost Gallons Cost 11/3/2014 120,428 $819.32 54,604 $819.32

5/8/2015 97,988 $652.07 45,628 $652.07

8/18/2015 160,820 $1,149.69 72,556 $1,149.69

11/2/2015 578,952 $4,453.60 258,060 $4,453.60

2/1/2016 63,580 $380.93 62,832 $974.50

5/2/2016 44,880 $233.82 43,384 $625.19

8/1/2016 132,396 $946.16 126,412 $2,208.75

The price of water and sewage have risen each year, the most recent rates are shown below.

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Table 1.10 Water / Sewer Recent Rates

Combined Water & Sewer Rates Units

FY 2015 FY 2016 FY 2017

0‐10 Water $1.65 $1.68 $1.71 Sewer $4.44 $4.53 $4.73

11‐20 Water $2.52 $2.57 $2.62 Sewer $7.91 $8.07 $8.43

21‐40 Water $3.73 $3.80 $3.88 Sewer $13.08 $13.34 $13.94

40+ Water $5.79 $5.91 $6.03 Sewer $13.08 $13.34 $13.94

Note: Units = 100 Cubic Feet = 748 gallons

Figure 1.13 shows water consumption, according to billing data.

Figure 1.13 Recent Water Consumption

Energy Use and Costs by Percentage Figure 1.14 shows the estimated break down of electric energy (kWh) use by category. Fans and pumps is the highest user group, followed by lighting, cooling, heating, computers and other.

Other includes kitchen appliances, office equipment, computers, elevator, fitness equipment, etc.

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Figure 1.14 – Electricity Use (kWh) by Category

Energy costs by category are shown by percentage of total costs which combines both electric costs and gas costs in Figure 1.15. Here heating leads followed by fans and pumps, lighting, cooling, other, DHW and computers.

Figure 1.15 – Energy Costs by Category

5. ENERGY CONSERVATION MEASURES

There are four main energy conservation measures (ECMs) recommended:

1 Re-pipe Heat Pump 2 EMS Improvements 3 Lighting Upgrades 4 Vendor Miser

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These ECMs are discussed in detail in this Section.

The costs and savings listed for each ECM is based on many assumptions and were estimated using Excel spreadsheet analyses and RS Means cost books, prior experience and contractor quotes.

Utility incentives for both electric and natural gas savings are available from Eversource under their existing programs.

ECM 1 Re-pipe Heat Pump Existing Condition:

The Readiness Center has a 100 Ton heat pump with four 25-ton scroll compressors that does not work correctly. The system was not plumbed wrong and commissioning after installation apparently never happened. Currently only the cooling side (50-tons) is operated in the summer to provide chilled water to the building. The heating side (50-tons) has never worked.

The building has a secondary loop that circulates hot or chilled water through the building. The building’s secondary loop is connected to the chiller’s evaporator with tees so that some of the pumped flow is induced through the evaporator. But evaporator flow is never fully established.

When the load of the building rises above what one compressor can meet the second compressor starts. However, because of the piping/flow problems the heat pump trips out on low refrigerant pressure/temperature and needs to be manually restarted. At restart both compressors can be brought on line. Because of the flow issues the performance of the heat pump is subpar.

Proposed Solution:

The heat pump needs to be re-piped into a primary/secondary system. This will ensure that proper flows through the evaporator barrel will occur. With proper flows, heat pump performance will increase and when the second compressor comes on the system will not trip out.

There are two options for re-piping. First is to pipe it as it should have been piped originally; as a primary/secondary system. A short loop with its own duplex pumping system would pump water through the evaporator barrel at the proper flows. The primary loop would share a section of piping with the secondary loop. The secondary loop would then receive chilled water from the primary loop and send it to the building. This option, while the correct way to go, is expensive. Inclusion of a duplex pump system raises the pricing to where it becomes not cost effective from solely an energy savings perspective. Costs for this option would be about $68,000 and simple payback would be over 30 years.

The other option would be to re-pipe the system so the full secondary flow goes through the chiller’s evaporator without adding additional pumps. This would be far less costly while still

Guardian Energy Management Solutions, Marlborough, MA Page 27 of 40 allow the chiller to work properly. This is the option summarized in the Economic Estimate table below.

The same could be done on the heating side to make it work properly.

Economic Analysis:

The existing situation produces much colder temperatures in the evaporator barrel due to inadequate water flow. The second compressor when it comes on quickly lowers the temperature even more and trips out the unit on low temp. The barrel temperatures are running at an estimated 36ºF, while with proper flow the barrel could be at least 10ºF warmer. Increasing the evaporator temperature saves about 2% of energy for every 1ºF and increase of 10ºF would increase performance by 20% (= 2% * 10ºF). With a warmer evaporator barrel the second compressor coming on would not trip out the unit.

Using an innovative design (passive valance units with heat recovery units), the building’s HVAC system was meant to operate at warmer chilled water temperatures. On all but the hottest days of the summer the building should be air-conditioned adequately by 48º or higher chilled water temperatures. Therefore an increase of 12ºF or more in the evaporator barrel temperatures is likely to be the norm, and a 20% increase in performance should be considered quite conservative.

Economic Estimate: ECM 1: Re-Pipe Heat Pump Electricity Natural Gas Total kWh kW $ Therms $ Savings 9,595 0 $1,938 0 $0 $1,938

Installed Cost

Utility Incentive

Net Installed Cost

Simple Payback Before Incentive

Simple Payback After Incentive

$14,000 $1,919 $12,081 7.2 years 6.2 years Note: Utility incentives are an estimate. Eversource determines the final incentives.

Comment:

This ECM needs to be done for reasons other than saving energy as the heat pump is being highly stressed and its life is being severely limited.

The heat pump could exchange energy with the earth through a ground-coupled heat exchanger;

this is discussed more in Part 3 – Alternative Energy Feasibility Study section of the report. This option is competing with heating from the gas-fired boilers that have efficiencies well above 90%.

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ECM 2 EMS Improvements Existing Condition The EMS (energy management system) is a Trane Tracer system. It provides full graphics and access to all user controlled component set points via graphics. It is a true marvel in assisting building operators to run their buildings’ HVAC systems. It offers alarms that warn when set points are off.

Even better, the EMS records data from its points. A point is an input or output from employed sensors, such as outside weather conditions, room temperatures, CO2 levels in the air, speed of fans and pumps, amount of air being circulated, hot and cold water and air temperatures, etc.

This data collection is called trending and plotted trend reports can be used to show if everything is working as it should and for maintenance diagnostics.

An EMS can be used as a sophisticated time clock to turn fans, pumps, boilers, chillers, etc. on and off according to an adjustable schedule. However, a simple 7-day time clock can do the same. There are other features of an EMS that should be utilized such as:

• Occupied set back: reducing room temperatures when the building is unoccupied.

• Control of exhaust fans: shutting them off when the building is empty.

• Closing OA dampers tightly during un-occupied times.

• Optimum Start and Stop: starting the building up in the morning on a just in time basis and letting it “drift” at the end of the day.

• Demand controlled ventilation (DCV): using CO2 as a proxy of occupancy to adjust ventilation rates.

• Hot water, chilled water and static pressure resets: adjusting temperatures and fan speeds to minimize energy usage.

The Readiness Center EMS seems to have most of these options available but either they are not working properly or the building manager was never trained to set up and use them.

Economic Analysis:

A summary of estimated energy savings, installation costs and utility incentives are shown below for all of the EMS Improvements. Savings estimates for the individual EMS improvements are provided under each ECM 2 subsection (ECM 2.1 thru 2.6) below.

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Economic Estimate: ECM 2: EMS Improvements Electricity Natural Gas Total

30,388 0 6,138 2,425 $2,231 $8,370

Utility Incentive

Net Installed Cost

Simple Payback Before Incentive

Simple Payback After Incentive

$25,000 $0 $25,000 3.0 years 3.0 years

Note: Utility incentives are an estimate. Eversource determines the final incentives.

ECM 2.1 Make EMS useful Existing Problem:

To be useful to the building operator the EMS needs to provide full and useful information.

Certainly alarms provide helpful information for points that are out of their normal rage of operation.