Anchorage Cooling Study Report Final 2.6.24.pdf

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Cooling Study Report

VA Anchorage Cooling Upgrade and Repairs Study Alaska Healthcare System 1201 N Muldoon Rd Anchorage, AK 99504

Final Report

VA Contract Number: 36C26018D0047 VA Task Order Number: 36C26023N0357 VA Project Number: 463-23-101

AES Project Number: VA201-2301

January 2024

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Table of Contents i

PART A – GENERAL DESCRIPTION

EXECUTIVE SUMMARY 1

EXISTING SYSTEM 1

FACILITY LOAD 2

ENVIRONMENTAL CONDITIONS 4

PART B – COOLING SYSTEM

CHILLER SYSTEM OPTIONS 5

STATUS QUO 5

GROUND SOURCE HEAT PUMP SYSTEM 6

AIR COOLED CHILLER SYSTEM 7

WATER COOLED CHILLER SYSTEM 8

RECOMMENDATION 9

THERMAL ENERGY STORAGE 10

ADDITIONAL ACTIONS

AIR HANDLER MODIFICATIONS 12

CHILLER SYSTEM UPGRADES 12

GLYCOL 13

ENERGY VALVES 13

COOLING COIL MAINTENANCE 13

HUMIDIFIER SYSTEM 13

COIL MAINTENANCE 15

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ELECTRICAL 16

ELECTRICAL SYSTEM ANALYSIS 16

NORMAL POWER 16

EMERGENCY POWER 16

POWER EXPANSION 16

COST ESTIMATING 17

PART C – APPENDICIES

APPENDIX A: COST ESTIMATE 18

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PART A – GENERAL DESCRIPTION

EXECUTIVE SUMMARY

The Anchorage VA Medical Center is a relatively new facility, with design completion in 2007. The cooling system has a unique design layout that has some advantages but also some flaws that need to be addressed. In addition to the overall system faults, most of the Air Handling Units (AHUs) have issues with scale build up on the exterior of the cooling coils, mostly from the humidifier systems. These problems together drive the need for this study of the cooling system as a whole. This report includes an evaluation of cooling system options, estimates of installation and operating costs, and a recommended course of action. For the cooling coil issues, the scale buildup and the cause will be assessed and AES will provide a recommendation between cleaning and replacement, and any corrections to the system to avoid future problems.

EXISTING SYSTEM

The facility cooling system consists of well water pumped from the underground aquifer and passed through a heat exchanger to cool the facility chilled water loop. The well water portion of the system is operated by a central plant, with utilities being shared between the Joint Base Elmendorf-Richardson (JBER) hospital and the VA Clinic. The Central Plant operates 4 wells including one well added as part of the VA Clinic construction. JBER pumps well water to the VA clinic and takes return water back where it is dumped to the storm sewer system. This very cold well water, typically around 42° F, is passed through one of two plate and frame heat exchangers in the clinic mechanical room; there it cools the facility glycol/chilled water loop. The facility loop is otherwise a typical loop with dedicated pumps, distribution piping to each AHU, and control valves managing the flow to each cooling coil.

JBER is a full hospital with critical patients while the VA Clinic does not have Emergency or Surgery departments. During high cooling load days, the well system cannot keep up with the load from both the JBER Hospital and the VA Clinic. In those situations, the Central Plant operators limit flow to the VA Clinic to maintain full cooling to the hospital. The clinic staff adjusts the chilled water and room temperature set points to reduce demand and distribute the cooling capacity as evenly as possible.

This system has some notable advantages, mainly its simplicity and low energy usage. This system has no compressors or refrigerant, making for a system that is simple to maintain and has few points of failure. This simplicity cascades down to the low original installation cost, BAS control system low complexity and cost, space usage, and future demolition and recycling costs. The refrigerant compressor is usually the highest electricity consumer in the system. The heat

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exchanger is a passive component and there are no fans as in a typical chiller system, leaving only the well pumps requiring power on what is typically the condenser side of the system. The glycol chilled water loop will remain as-is so those components will generally be ignored in the assessment and comparison.

This system has some significant disadvantages. This system uses ground water in a single pass through the system before it is dumped to local waterways. The system has too little ground water capacity to support the JBER Hospital and the VA Clinic simultaneously. A well was added during the VA Clinic construction but did not adequately increase the system capacity. Additional wells have been discussed, as well as deeper wells to reach more ground water. This highlights a major issue with this type of system: the system is not sustainable. Groundwater may seem infinite, but the constant pumping of a significant amount of water is lowering the depth of the aquifer. This will require deeper and deeper wells to maintain flow. The groundwater is used by other people and businesses; overuse of this resource significantly impacts others.

Responsible use of our natural resources is something that is expected of our government. This system has issues with capacity, sustainability, long term viability, and the complication of the shared system with the JBER Hospital. For these reasons, we recommend the system be replaced with an independent system of a different format for sustained future use of the VA Clinic.

FACILITY LOAD

The load side of the chilled water system includes ten air handlers (AHU-8 has a chilled water coil and a DX coil for additional dehumidification, both are included in the total), 12 water cooled air conditioning units for telecom rooms (ACU1-12), two Computer Room Air Conditioners (CRAC) (ACU-13 and 14, scheduled at 10 tons but currently installed equipment is 25 tons), and two small water cooled AHUs in stairway vestibules. The total load is 415 tons but this is the total of peak loads, there may be some reduction based on alignment of the peaks of individual pieces of equipment. It is advisable to include some extra capacity for future needs. A 10% buffer would yield about 460 tons of total cooling for the entire facility.

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Table 1. Facility Cooling Loads

FACILITY COOLING LOADS

SYSTEM TAG SCHEDULED TOTAL CAPACITY

Tons MBH (1000 Btu/Hr)

AHU-1 50.8 610

AHU-2 51.3 615

AHU-3 51.3 615

AHU-4 58.1 697

AHU-5 45.3 543

AHU-6 20.3 243

AHU-7 11.3 136

AHU-8 13.2 158

AHU-8 DX 31.6 379

AHU-9 4.8 57

AHU-11 7.8 93

ACU-1 1 12

ACU-2 1 12

ACU-3 1 12

ACU-4 1 12

ACU-5 1 12

ACU-6 1 12

ACU-7 1 12

ACU-8 1 12

ACU-9 1 12

ACU-10 1 12

ACU-11 1 12

ACU-12 1 12

ACU-13 25.2 302

ACU-14 25.2 302

ACU-15 5 60

ACU-16 2 24

Overall System Capacity 414.8 tons 4,978 MBH 10% Buffer 41.5 tons 498 MBH Total 456.3 tons 5,476 MBH

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ENVIRONMENTAL CONDITIONS

The climatic conditions in Anchorage are generally cool. The design conditions from the ASHRAE Handbook - Fundamentals 2021 offer climate tracking data in several metrics, including Cooling- Degree-Days (CDD). CDDs measure how many days in an average year the temperature will exceed a given threshold (50°F and 65°F, in this case) and by how much.

*Assume "Average Daily Temp for 1 day" = ADT1 IF (ADT1>50°F), THEN (ADT1 - 50°F)*1 Day = X CDD50 IF (ADT1>65°F), THEN (ADT1 - 65°F)*1 Day = X CDD65

CDD Total = Sum of the value of all ADT1 per year

Annual totals for Anchorage are shown below, with data from the AES office in Parker, CO, and a random sample in Houston, TX for comparison. This illustrates the relatively low climate load.

Much of the cooling load is from internal sources and isn’t dependent on outside temperature, but each main AHU is equipped with an economizer. This allows it to bring in cooler outside air to offset the demand on the cooling system, up to 100% of the airflow and load. With a typical supply air target of 55°F, the load can be managed with the economizer when outdoor temps are below 55°F, removing that unit’s demand on the chilled water system. The cool outside air will fully cover the cooling load by meeting the air handler supply air target without utilizing the cooling coil. There are other components of the system that can’t rely on outside air and have a high internal load such as IT closet fan coils (ACU-1 through 12 above), and server room CRACs (ACU-13 and 14). The cooling system can never fully shut down as these are 24-hour operations and have a significant cooling load. Current system limitations require operating at “occupied” setpoints 24/7 as there isn’t enough capacity to recover from nighttime setbacks. This consumes additional electricity and water for cooling, and heating energy for interior reheat. ACU-15 and 16 serve stairwells with an all-glass exterior envelope. That means they have no internal load and a large envelope load, making the internal temperature highly dependent on solar gain.

Table 2. Annual Cooling design conditions

Annual Cooling Design Conditions

0.4% Design Day - ASHRAE 2021 Dry Bulb Temperature (DB) Wet Bulb Temperature (WB)

74.5° F 59.0° F

Table 3. Cooling Degree Days

Cooling Degree Days – ASHRAE 2021 Anchorage, AK CDD 50 879 CDD 65 109

Parker, CO CDD 50 2788 CDD 65 675 Houston, TX CDD 50 8258 CDD 65 3682

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PART B – COOLING SYSTEM

CHILLER SYSTEM OPTIONS

STATUS QUO

The existing system has the advantages of electricity consumption and simplicity but also flaws that make the system problematic. Current operations are not meeting facility requirements on high demand days. As mentioned earlier, expansion of the existing system is not feasible;

significant work is required including a new system type.

To set the baseline, we’ll cover the layout of the current system. Figure 1 shows the main components of the system. There are three sections to look at. The left side shows the facility hydronic cooling loop, this portion will remain mostly unchanged. The piping and pumps will be largely unchanged. Pumps 13A and 13B could be 1:1 replaced as part of the construction work.

The right side is operated by JBER to provide cold well water to the VA Clinic and their own cooling system as well as the JBER Hospital domestic water and fire protection demand. The heat exchangers in the center are passive units that transfer heat out of the glycol cooling loop and into the well water that eventually becomes wastewater.

Figure 1 Existing system schematic

The simplicity and efficiency of this system (assuming it met setpoints) are the highest of any of the options. The gains on efficiency and operating costs are unfortunately nullified by system capacity limitations. Improvements to the capacity of the existing format would be temporary and unsustainable.

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GROUND SOURCE HEAT PUMP SYSTEM

Ground Source Heat Pump (GSHP) systems are typically expensive to install due to the amount of earthwork and the wellfield, but are highly efficient due to consistently lower condenser water temperature. They require a well field that can be configured in several different ways, mainly a vertical vs. horizontal well field, and closed-loop vs. open-loop systems. Open-loop systems take natural ground water for cooling and can return water to the ground through a discharge well or released as surface water.

Figure 2 Ground Source Heat Pump system schematic

A closed-loop system would be very difficult to utilize due to the land area required by the well field for a system of this scale. This is not viable for this facility outside of the initial construction.

However, the existing system is essentially an open-loop ground source system without the compressors. A Water Source Heat Pump (WSHP), the central equipment of a GSHP system, could be added to the existing system in place of the heat exchangers. This would allow the system to expel far more heat to a smaller volume of well water or use the JBER Hospital well water waste stream. Permitting for a discharge well is complicated and risky. If a permit is not attained, this option would have to discharge water to a storm drain as it does now.

Advantages of an open-loop GSHP system would include high efficiency and low construction impact. All equipment would be located inside as it is currently. Maintenance would increase from the existing system as it adds water cooled chillers but is relatively low compared to other options presented. The chillers are similar to those in a water-cooled system so local maintenance parts and service should not be a problem.

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A water-cooled chiller of appropriate capacity is roughly 10’L x 6’W x 6’H each, not including space for maintenance, two required. These can likely be installed in the space vacated by the existing heat exchangers and other equipment in the mechanical room that is no longer used.

AIR COOLED CHILLER SYSTEM

Air cooled chiller systems are very common and are the most conventional application for small and medium sized facilities. They are the simplest component to drive a hydronic chilled water system. Installation costs will be the lowest of the possible options and maintenance is uncomplicated and finding local service and parts should be straightforward. This system would also take advantage of the generally cooler outdoor temperatures in Anchorage.

Figure 3 Air Cooled system schematic

This system type is the least efficient of the options, with an average system using about 1.2 kW/ton of cooling, positioning this as the low up-front costs, higher operating costs option. This is a generalization based on the average system and includes pumping costs as well as the chiller operation. Air cooled chillers must sit outside exposed to the elements and occupy space that was not accounted for in the site layout. The chillers needed for this facility, two 200-ton chillers as an example, are approximately 30’ long by 8’ wide, not including clearance needed for airflow and maintenance. A single 400-ton chiller is over 45’ long. Maintenance requirements are on par with a ground source system with the disadvantage of outdoor equipment taking more wear from the environment and complicating work during extreme weather.

The cooler climate in Anchorage means the chiller would operate less compared to the same equipment in a hotter location; this skews the balance of operating cost vs installation cost.

Cooling equipment efficiency matters less because it doesn’t operate as often, upfront costs then become more significant. A water-side economizer on an air-cooled chiller allows the unit to

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further reduce operating hours by providing some cooling when outside temps are low. This will often fully cover the IT load during winter months.

A rough energy model was created of the same building in Anchorage and Houston. The increased environmental load in Houston required almost 40% higher electricity consumption over the course of a typical year. Using an example chiller, a 20°F difference in peak outdoor temperature, roughly the difference between Anchorage and Houston, decreases a chiller capacity by around 10%; increases electrical load at max capacity by around 20%; and reduces the chiller EER (Electricity Efficiency Ratio, the refrigeration capacity at full load (in watts) to electrical input power (in watts)) by about 25%. There’s no information shared if the energy modeling software accounts for this performance reduction, but in short, you get more value out of an air-cooled chiller in the generally cooler environment in Alaska than you might expect in the continental US.

WATER COOLED CHILLER SYSTEM

The last type to choose from would be a water-cooled chiller system. This arrangement consists of chillers, cooling towers, and the associated piping and pumps to connect the two. They are common on large buildings up to full campus systems. These can be as small as 50 tons up to thousands of tons and essentially infinitely expandable. Water cooled systems are more efficient than air cooled units, using roughly 0.6 kW/ton on average. While they are more complex than air-cooled systems, they are common enough in the area that parts and maintenance should not be a problem. A water-side economizer is also available on water-cooled chiller system and permits a reduction in operating hours.

Figure 4 Water Cooled Chiller system schematic

Water cooled chillers are in the higher up-front costs/lower operating costs point on the cost spectrum. They are more complex and have more components than air cooled systems with more points of failure and more maintenance actions required. Typical open-loop cooling towers

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require an open bath of water outside and cannot use glycol antifreeze. While they can operate below freezing temperatures, they have limitations. Ice buildup is a concern, and extreme low temperatures and extended shutdown periods can be problematic. Open-loop cooling towers should be eliminated as non-viable. Closed-loop cooling towers can use antifreeze but still utilize an open bath of untreated water outside. This can be drained, but this process adds more cost and time for the maintenance personnel. Overall maintenance is similar to the ground source system but adds outdoor cooling towers with their own periodic maintenance and repairs, and complications with untreated water below freezing temperatures.

A water-cooled chiller of appropriate capacity is roughly 10’L x 6’W x 6’H each. These can likely be installed in the space vacated by the existing heat exchangers and other equipment in the mechanical room that is no longer used. Cooling towers are roughly 10’L x 6’W x 10’H each. Two of each are needed and doesn’t include space for maintenance and airflow.

Water cooled chillers enjoy the same benefits of cooler outdoor temperatures as an air-cooled chiller. But the point above is chillers use less electricity and run more efficiently at cooler outdoor temp and that makes incremental improvements in efficiency and power usage take longer to justify the extra investment compared to a similar system in the continental US.

RECOMMENDATION

The three systems discussed were entered into a rough energy model for electrical calculations.

The output includes many details, but the primary focus is the electrical consumption of the chiller system alone. All other parameters such as HVAC fans, lighting, and interior plug loads are the same between the options. The cost below assumes an average electricity cost of $0.1049/kWh.

Electricity Consumption

System Type

System Pumps Total Total Cost Per Year

Cost Diff Per Year

% Change From Baseline kWh/year kWh/year kWh/year

Air Cooled Chiller 474,994 14,567 489,561 $51,355 - - Water Cooled Chiller 366,411 39,014 405,425 $42,529 $8,826 -17.2% Open-Loop GSHP 333,958 101,244 435,202 $45,653 $5,702 -11.1%

As shown, considering the air-cooled chiller system as the baseline, the other two options have lower consumption. Of course, the bulk of the consumption comes from the chiller itself (and cooling tower fans), in the cooling system column above. The air-cooled system has the largest consumption in this category but has the lowest pump energy consumption. This accounts for just the existing glycol loop pumps as there is no other water loop or pump. The water-cooled chiller and cooling towers use noticeably less electricity, about 23%, but the additional condenser loop adds another pump bringing the difference to only about 17% less consumption. The ground

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source heat pump uses the least energy, partly because there is no condenser fan, but has additional pumping requirements for the ground loop, reducing the improvement to around 11% less than the baseline.

Construction costs also vary for each system type. Complete cost estimate is included below. The Return On Investment (ROI) shown is a simple calculation of the construction cost difference divided by the energy cost savings and does not include maintenance costs, inflation, etc. Typical estimated lifetime of indoor HVAC equipment is 30 years.

Construction Costs System Type

Total Estimated Cost

Cost Difference From Baseline

% Change From Baseline

Approximate

ROI

Air Cooled Chiller $1,156,511.09 - - - Water Cooled Chiller $1,782,354.98 $625,843.89 54.1% 70 yrs Ground Source HP $1,702,668.67 $546,157.58 47.2% 95 yrs

These calculations make several assumptions that could impact the results above, including condenser water delta T and pump head. Both of which can significantly impact pumping energy requirements. Additionally, similar chillers can vary widely regarding cost and efficiency. A 200-ton air cooled chiller in the Trane product line can vary from $180k to $300k for equipment that has the same capacity and fills the same role. The different product lines have different compressor types and other efficiency changes, making the more expensive chiller have a lower life cycle cost between the two. More refined calculations during the design process would change the results, and design decisions could minimize some of the shortcomings of each system type.

The water-cooled system adds additional components that require additional maintenance and attention (freeze protection in condenser loop) and higher up front construction costs. The GSHP system maintenance should be similar to the air-cooled system but has higher upfront construction costs. These additional costs blunt the advantage of the more energy efficient systems.

Because of the long ROI, more complex maintenance and reduced advantage of the more efficient water-cooled system and GSHP, the assessment suggests the air-cooled system as the best choice.

THERMAL ENERGY STORAGE

A possible add-on component would be a Thermal Energy Storage (TES) system, also known as ice storage or thermal battery. There are many ways to configure this equipment. It still requires a chiller of some sort, either air cooled or water cooled, but adds a large tank or tanks to pre-cool

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a glycol solution to use later. Valves in the system can change the system between normal chiller operation, ice tank operation, or a combination of both. This takes advantage of the electricity provider’s billing plans by averaging load to reduce demand spikes and allowing smaller equipment with lower peak demand to reduce demand charges.

Figure 5 Thermal Storage Electrical Loading - Courtesy Trane

This has the potential to reduce the electrical construction costs and operating costs, as well as chiller size and associated construction costs. This also adds some redundancy and expands the possibility for water side economizer energy savings.

Figure 6 Thermal Storage Chiller system schematic

This system is more complex and requires more complex controls, but the additional equipment is mostly the passive ice storage tanks and commonly available control valves. The maintenance is no more complex than a typical air-cooled system. The additional complexity and equipment make for higher construction costs, somewhat offset by smaller or fewer chillers and reduced electrical equipment construction costs. Despite the extra upfront cost, payback can be as little

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as two years and typically less than four years, depending heavily on decisions made during the design process.

ADDITIONAL ACTIONS

There are several actions that could be taken that could increase efficiency, reduce energy usage, and reduce equipment and maintenance costs. These would be undertaken as part of the chiller system design and construction, or as independent projects.

AIR HANDLER MODIFICATIONS

Several of the air handlers provide 100% outside air (OA) to various spaces in the clinic, specifically AHUs 7, 8, and 9, serving Dental, Surgery, and Lab spaces respectively. Some of these space requirements have changed, creating some opportunities for energy savings and reduced system load. Lab spaces still require 100% OA so that system will remain unchanged.

Dental facilities no longer require 100% OA per VA HVAC Design Manual, Nov 2023, section 6-50.

The layout of AHU-7 and the exhaust fans for the space would require relatively minor changes to convert the system to a return air system. This would allow the system to heat or cool more temperate return air rather than extreme outside temperatures, saving significant heating or cooling energy.

AHU-8 serving Surgery is in the same position, per VA HVAC Design Manual, section 6-179. In addition to that, the space is not operating as a surgical suite and is likely to be renovated to serve another purpose in the future. The Return Air (RA) and Exhaust Air (EA) systems could be adjusted in the same way as AHU-7 to meet the requirements of whatever usage that space ends up as.

CHILLER SYSTEM UPGRADES

Most of the systems listed have capabilities of adding energy recovery and economizers of various forms. A water-side economizer would be particularly beneficial, allowing the system’s outdoor heat exchanger to provide compressor-less cooling during the winter for the data systems that require cooling full-time. This would either be part of the chiller product selection or some additional valves, piping, and controls sequences as part of the design and construction.

Some chillers have a heat recovery feature that will reject some of its heat to a hot water loop rather than as waste heat outside. This can provide hot water to VAV reheat coils when there is only a small load for dehumidification, for example, without running the boiler. This would probably operate less than an economizer and ROI may be lower, but could be investigated during the design phase to determine likelihood of payback.

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GLYCOL

This recommendation is rather controversial for a facility in Anchorage. The current chilled water system uses a mixture of 30% ethylene glycol and 70% water. The VA HVAC Design Manual, Nov 2023, section 4.2.5.1, advises using pure water in the chilled water system; insulation, heat tape, and control strategies should be utilized instead. When freeze protection is necessary, ethylene glycol is prohibited and should use propylene glycol; Design Manual section 3.2.1.6. Glycol reduces the heat transfer efficiency of the fluid, reducing the effectiveness of coils and heat exchangers, and increasing pump energy usage. None of the chilled water system is outside so heat tracing is not necessary. The only exposed locations are the cooling coils themselves. In the event of a failure, the coil control valve can be fully opened, keeping water moving through the coil and not freezing.

ENERGY VALVES

Energy valves are a relatively new special type of control valve that monitors coil Entering Water Temperature (EWT) and Leaving Water Temperature (LWT) and adjusts the flow to ensure the coil is producing the full temperature differential designed into the system. They have the advantage of increasing coil, heat exchanger, and chiller effectiveness; and reducing water flow, pump energy, and overall energy consumption. Installation can be straightforward but will add more points and sequences to the control system. They can be added individually, there is no need to upgrade the entire system or do everything at the same time.

COOLING COIL MAINTENANCE

The cooling coil in each of the nine main air handlers has significant scale build up on the coil fins and corrosion on the steel framework inside the air handler. The scale buildup can appreciably reduce the coil performance, heat transfer, cutting airflow or increasing fan energy usage, and impacting the coil’s ability to pull heat and moisture out of the air. The primary cause of the scale was the original humidifier system in each unit.

HUMIDIFIER SYSTEM

The original equipment layout used air atomizing humidifier distribution manifolds that were fed by plain tap water. This type of humidifier is adiabatic; it doesn’t add any heat to the system. The moisture is more of a cool mist rather than steam, meaning that water is more likely to collect on interior surfaces of the AHU. This led to significant condensate that had higher levels of minerals collecting on the cooling coil. Recently the humidifiers were replaced with a new system consisting of dedicated boilers fed by Reverse Osmosis (RO) water. This system has reduced

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condensate and much lower levels of minerals, removing about 98% of scale causing impurities.

The scale buildup should be largely eliminated, reduced to normal levels.

Looking at AHU-1 and H-1 as an example, the original design documents list a load requirement of 310 lbs/hr. That can put the occupied space, at around 95% RH (Relative Humidity). Except to get to that point at 70° F, the 55° supply air is past 100% RH, meaning water would essentially rain inside the AHU and condense on everything until the dew point dropped below the temperature of the surfaces in the air flow path.

Conversely, the new humidifier system in AHU-1 is specified at 134 lbs/hr. This rate can raise the space humidity to 40% RH (minimum for most spaces is 20% RH). This would put the 55° F supply air at about 68% RH and a dew point of 45° F, much colder than any of the surfaces inside the air handler after the preheat coil. This will eliminate temperature-based condensation anywhere past the absorption distance.

The new humidifier manifolds are located in the same place as the original installation. The absorption distance varies between each air handler. Original design documents listed a requirement for a 30” minimum distance from the manifold to the cooling coil. This is not met in some of the air handlers. Where it is not met, the component spacing won’t allow it. The two air handlers that don’t meet the minimum distance have the manifold pointed upstream to increase the humidifier effectiveness.

AHU HUMIDIFIER INSTALLATION DETAILS

SYSTEM

TAG

INSTALLED ABSORPTION

DISTANCE

MANIFOLD

ORIENTATION

CALCULATED REQUIRED

ABSORPTION DISTANCE

AHU-1 42” Downstream 39” AHU-2 46” Downstream 39” AHU-3 43” Downstream 39” AHU-4 10” Upstream 18” ** AHU-5 7 1/2” Upstream 8” ** AHU-6 34” Downstream 12” AHU-7 38” Downstream 30” AHU-8 38” Downstream 23” AHU-9 36” Downstream 34” AHU-11 None NA NA

**Upstream orientation adds approximately 24” to absorption distance capabilities.

All the air handlers now have the required clearance between the humidifier array and the cooling coil. This will eliminate any significant condensation on the cooling coil. If there is any, it

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will be far less than during cooling operations on a humid day. With the new steam humidifiers utilizing RO water and an appropriate installation, there will be no condensation and no further scaling on the cooling coils. To eliminate any possibility of condensation, there is an available upgrade to the humidifier controls for an AHU-mounted humidity high limit sensor to control the humidifier output based on actual conditions inside each unit. This will completely eliminate any possibility of condensation on the cooling coils. Otherwise, no changes are necessary.

COIL MAINTENANCE

The issue is then how to deal with the scale already built up on the coils. Coils can be cleaned to remove scale. Cleaning can have varying levels of effectiveness depending on the number of rows and fins per foot of the coil, data shown below, and if the coil is removed from the air handler or cleaned in place. Denser fin count and more rows makes it harder to get cleaning solution and water spray into the coil and get the scale buildup out. Alternatively, the coils can be replaced outright. This would obviously be more effective than cleaning and also includes any possible buildup inside the coil tubes as well. Replacement will be a significantly higher cost, but also restarts the clock on age of the coil and when it eventually needs replacement. An issue with replacement, or removal for cleaning, is that some of the air handlers do not have sufficient clearance to fully remove the coil from the unit. Most are issues are from other equipment. This equipment could be moved, which adds additional cost and complication to the process. Others are blocked by fixed obstructions, e.g. stairs or other building components.

COIL DATA

UNIT

NUMBER

FINS PER

FOOT

COIL

ROWS

FACE AREA

(SF)

REPLACEMENT

COST (COIL ONLY)

REPLACEMENT COST

(W/LABOR, MARKUPS,

ESCALATION)

AHU-1 137 8 65 $30,790 $76,664

AHU-2 110 10 65 $30,790 $76,664

AHU-3 110 10 65 $31,018 $77,144

AHU-4 134 8 75 $32,675 $80,635

AHU-5 158 8 58 $33,744 $82,887

AHU-6 152 10 23 $28,580 $72,008

AHU-7 153 8 14 $12,389 $35,538

AHU-8 160 8 15 $7,960 $26,208

AHU-9 152 6 6 $4,584 $19,095

AHU-11 124 8 8 $5,125 $20,235

TOTAL $217,655 $520,286

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The recommendation for restoring the coils to their original performance is to have each coil cleaned and descaled. An outside contractor has the time and equipment necessary as well as the expertise and experience to do the most effective job possible. Awarding a new contract for that work can be independent of the chiller system work and should happen as soon as possible.

This will restore the coils to their best performance available and reap those benefits as soon as possible.

ELECTRICAL

ELECTRICAL SYSTEM ANALYSIS

The electrical system description below was gathered from existing drawings from project number 463-500 dated 02/26/07 and from photos provided by the Anchorage VA.

NORMAL POWER

The utility providing power to the hospital is Chugach Electric Association through two step down transformers; 1000kVA “TXSA” and 500kVA “TXSB”. The primary winding of the transformers are connected and they step down the voltage from 12470GY/7200V to 480Y/277V. The main normal power to the hospital is powered by a 3000A, 480Y/277V, Square D switchboard fed from “TXSA” and by a 1200A, 480Y/277V main distribution switchboard “NMDSB” fed from “TXSB”.

EMERGENCY POWER

A 550kVA, 480Y/277V standby generator provides emergency power via a 1200A distribution panelboard “EMDS” to two essential branches for the hospital. The essential system has two critical branches fed by a 100A and a 225A ATS, and two life safety branches fed by two 60A ATS’s.

There are no dedicated equipment branches present in the hospital. All the mechanical equipment that requires emergency power is on the critical branch.

A healthcare facility with only Category 2 or lower spaces, such as nursing homes or limited care facilities, would have a Type 2 Essential Electrical System (EES) that only needs two branches (Life Safety and Equipment).

POWER EXPANSION

Analyzing the one-line diagram, and panel schedules from Project Number 463-500 “New VA Outpatient Clinic and Regional Office Building”, the normal power main distribution board has 729 amps at 480V of spare capacity.

COOLING UPGRADE AND REPAIRS STUDY COOLING STUDY REPORT

ANCHORAGE, AK JANUARY 2024

Size

(Amps) Used kVA Used Amps

NMDSA1 3,000 Section 1 1741.4 2094.6 Section 2 146.6 176.4

Total Load 1,888 2,271

Available Space Remaining 729 A

To add any mechanical equipment, such as chillers or AHUs, an equipment branch needs to be created in the Essential Electrical System (EES) since one does not exist. It can be created by adding a 600A ATS and connecting it to one of the spare breakers in the main distribution switchboard.

The emergency distribution switchboard EMDS is at capacity. It is a 1200A switchboard and it is loaded 839.7A. A new emergency distribution switchboard will be needed if a 600A ATS is added to the electrical system.

If something larger than the 600A ATS is needed to accommodate the new mechanical system, the utility will have to upgrade the feeder from a 3000A feeder to a 4000A. For example, one 215 nominal tons chiller requires about 330A at 480V. If a redundant system is required, then this will be a scenario where the utility will have to be upsized.

COST ESTIMATING

Cost estimate can be found in the Appendix. The cost estimate shows the (3) design options.

COOLING UPGRADE AND REPAIRS STUDY COOLING STUDY REPORT

ANCHORAGE, AK JANUARY 2024

PART C – APPENDICIES

APPENDIX A: COST ESTIMATE

On Following Sheet

Cooling Study Report

DEPARTMENT OF VETERANS AFFAIRS

VA Anchorage Cooling Upgade and Repairs Alaska Healthcare System 1201 N Muldoon Rd Anchorage, AK 99504

Project Number VA201-2301 463-23-101

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I EXECUTIVE SUMMARY

AES Group was tasked with providing a cost estimate, utilizing the Conceptual Documents as a guide, which was prepared by the A/E, AES Group

This project consists of generating conceputal cost estimates for (3) different cooling design options that are to serve the Anchorage VA Medical Center.

The project may include work for the existing site and its building utilities. It is anticipated that this work will be performed in 8-hour shifts, Monday through Friday, during normal business hours with night and weekend work as necessary. The estimate assumes the project will be constructed under Service Disabled Veteran Owned Small Business, set aside, and the cost estimate has been priced for construction by a General Contractor utilizing subcontractors for the majority of the work.

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II PROJECT INFORMATION

Designer AES Group Estimator Akeno Hutchinson (AES Group) Owner Project Location 1201 N Muldoon Rd Anchorage, AK 99504 Estimate Class/Methodology Class 5 Estimating Software RSMeans Work Breakdown Structure (WBS) CSI Format Project Number VA201-2301 Basis of Pricing City Cost Index RS Means; Historical VA & Subcontractor Data; Estimato Method of Measurement Imperial (US Standard) Currency United States of America Dollar Design Mission Renovation Building Type Masonry/Concrete Roof Type Unknown Building Utilization Hospital Number of Buildings N/A Demolition Yes Hazardous Materials Yes Site Work Yes

PROJECT SCOPE

Drawings Conceptual Documents Estimate Date Sunday, December 31, 2023 Design Analysis Yes Site Visits Attended N/A Discussions N/A Previous Estimating Comments N/A Estimator Akeno Hutchinson

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Quantity Material Cost/Unit

Unit Total Cost/Unit Unit

L1 L2 L3

D D30

D

D D30

D D30 2 $750,000.00 $375,000.00 ea $395,400.00 ea

D D30 2 $19,000.00 $9,500.00 well $19,000.00 well

D D30 400 $30,292.00 $75.73 lf $91.60 lf

D D30 1 $0.00 $0.00 ls $1,076.00 ls

D D30 1 $27,110.60 $27,110.60 ls $42,038.60 ls

D D30 1 $0.00 $0.00 ls $490,619.48 ls

D D30 1 $0.00 $0.00 ls $19,716.48 ls

D D30 1 $0.00 $0.00 ls $283,778.11 ls

D D30

D D30

D D30

D D30 2 $530,000.00 $265,000.00 ea $284,000.00 ea

D D30 75 $5,088.75 $67.85 lf $82.68 lf

D D30 1 $0.00 $0.00 ls $1,076.00 ls

D D30 1 $27,110.60 $27,110.60 ls $42,038.60 ls

D D30 1 $0.00 $0.00 ls $333,350.42 ls

D D30 1 $0.00 $0.00 ls $13,227.90 ls

D D30 1 $0.00 $0.00 ls $192,778.78 ls

D D30

D D30

D D30

D D30 2 $750,000.00 $375,000.00 ea $395,400.00 ea

D D30 2 $106,200.00 $53,100.00 ea $57,037.50 ea

D D30 50 $3,786.50 $75.73 lf $91.60 lf

D D30 20 $1,357.00 $67.85 lf $82.68 lf

D D30 1 $0.00 $0.00 ls $1,076.00 ls

D D30 1 $27,110.60 $27,110.60 ls $42,038.60 ls

D D30 1 $0.00 $0.00 ls $515,280.53 ls

D D30 1 $0.00 $0.00 ls $15,784.58 ls

D D30 1 $0.00 $0.00 ls $297,057.66 ls

D D30

D D30

Geothermal well

Underground well piping

Remove heat exchanger

Ground source HP system misc (pumps, SDVOSB, contractor, and subcontractor

Locality labor markup (24%)

Escalation to late 2027 (20%)

200 ton air cooled chiller

Piping and connection to pumps in building ls ls

$13,227.90 $0.00

$13,227.90

$0.00

$0.00 $0.00

$0.00

$0.00 ls

$6,201.00 $1,076.00 $42,038.60 $333,350.42

$1,156,672.70 ea lf ls ls ls

$13,227.90 ls $192,778.78

VA Anchorage Cooling Upgade and Repairs Alaska Healthcare System Cooling Study Report 31 December 2023

$0.00

Labor Cost Labor Cost/Unit Equipment Cost

Equipment Cost/Unit

Unit Total AmountUNI Div Description Unit Material Cost Unit

Ground Source Heat Pump System

D30 HVAC

200 ton water cooled chiller

Ground Source Heat Pump System Total

Air Cooled Chiller System

$790,800.00 $114,075.00 ea ea

$0.00

$0.00$0.00 $20,400.00

$3,937.50

$40,800.00 $7,875.00

$0.00ea $38,000.00 $19,000.00 $0.00 $568,000.00ea

$4,580.00 $1,653.60 lf lf

$0.00

$0.00

$0.00 $0.00

$15.87

$14.83

$793.50 $296.60 ea

$0.00lf $1,112.25 $14.83 $0.00lf

$1,076.00 $42,038.60 $515,280.53 ls ls ls

$0.00

$0.00

$0.00

$0.00 $0.00 $0.00

$1,076.00

$14,928.00

$515,280.53

$1,076.00 $14,928.00

$0.00

$0.00ls $1,076.00 $1,076.00 $0.00lsRemove heat exchanger

$1,782,345.98 ea lf lf ls ls ls ea ea lf

$0.00ls $14,928.00 $14,928.00 $0.00lsAir cooled chiller system misc (pumps, lf ls ls ls

200 ton water cooled chiller

200 ton cooling tower

Chilled water pipe from cooling tower to

Piping and connection to pumps in building

Remove heat exchanger

Water cooled system misc (pumps, valves, $0.00ls $0.00 $333,350.42 $0.00lsSDVOSB, contractor, and subcontractor

SDVOSB, contractor, and subcontractor

Locality labor markup (24%)

Escalation to late 2027 (20%) ls ls ls ls

$15,784.58 $0.00

$15,784.58

$0.00

$0.00 $0.00

$0.00

$0.00 ls

Air Cooled Chiller System Total ls ls

Locality labor markup (24%)

Escalation to late 2027 (20%) ls

$15,784.58 $297,057.66

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Water Cooled Chiller System

$0.00

Water Cooled Chiller System Total ea $40,800.00 $19,000.00 $6,348.00

$0.00 $0.00$19,716.48 well lf ls ls ls ls ls

$1,076.00 $14,928.00

$0.00 $19,716.48

$0.00 well lf ls ls

$490,619.48

$0.00

$20,400.00

$9,500.00

$15.87

$1,076.00

$14,928.00

$490,619.48 ls ls ls ea

$0.00 $0.00 $0.00 $0.00 $0.00

$0.00

$0.00

$1,702,668.67

$0.00

$0.00

$0.00

$0.00

$0.00

$0.00

$19,716.48 $283,778.11 ea well lf ls ls ls ls ls

$790,800.00 $38,000.00 $36,640.00 $1,076.00 $42,038.60

Thank You.

End of Estimate

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COST ESTIMATING