City of Westminster City Hall Server Room HVAC Study of Westminster City Hall Server Room HVAC Study ... This report analyzed existing mechanical and electrical ... With operating

City of Westminster City Hall Server Room HVAC Study

Prepared For: Tom Ochtera, LEED-AP, CEM Energy and CIP Coordinator

City of Westminster 6575 West 88th Ave.

Westminster, CO 80031 (303)658-2551

Prepared By:

1626 Cole Blvd. Suite 300

Lakewood, CO 80401 April 28, 2015

Executive Summary

The City of Westminster (COWM) requested Beaudin Ganze Consulting Engineers, Inc. (BGCE) provide three mechanical and electrical engineering system options and recommendations for server room HVAC upgrades at the City Hall building. This report analyzed existing mechanical and electrical systems and capacities, and outlines 3 potential upgrade options with simple Return on Investment (ROI) analysis. The analysis indicated the City of Westminster already follow the most logical and cost-effective cooling strategy. When existing equipment in place fails or reaches the end of its life, it should be replaced with similar sized equipment as discussed within this report.

I. Introduction

A. Beaudin Ganze Consulting Engineers had been retained by City of Westminster to review

existing HVAC systems installed for the City Hall Server room and provide three system options for upgrade consideration including simple ROI.

B. The intent of this report is to: 1. Analyze existing server room to identify required system cooling capacity. 2. Identify three system options capable of addressing server room. 3. Provide Rough Order of Magnitude Cost for system options 4. Provide Simple Payback Analysis for review. 5. Enhance the decision making process. 6. Be a basis for future facility upgrade decisions. 7. Assist with selection of options and future upgrade design.

C. This narrative, its appendices, and supporting attachments describe our findings and

recommendations and provide an overview of scope anticipated for each of the three system options presented.

D. Information contained herein is the result of field reviews conducted during the fall of 2014 and Spring of 2015, interviews with facility maintenance and operations staff, review of available drawings and submittal information, pricing data from 2013 RS Means and Data Aire manufacturer’s representative, engineering judgment, and experience.

II. Findings

A. Existing Conditions

1. The existing city hall server room is approximately 1000 sq.ft. Room

temperatures are maintained as low as 68 degrees. Humidity levels are maintained near 40%. The room is located on the lowest level, and has one exterior wall (below grade).

2. There are currently 10 open-style racks (not cabinets) of equipment in the room (6 racks for servers and 4 for distribution). They are arranged in a single row with a hot side and cold side.

3. The facility used to have as many as 100 servers in the space, but is shifting towards cloud-based computing. Approximately 30 servers exist in the room today.

4. Electronic storage capacity needs are projected to double in four years. As

storage is added to the room, it is anticipated they will be Solid State style.

5. The server room requires a redundant backup cooling system to maintain operation at all times.

6. The server room has a UPS system 40kVA for providing power to the servers.

At the time of the visit the draw was displaying 16.7kVA, 42% capacity.

7. The cooling systems installed for the room include:

a. (1) 8 year old, 10 Ton, DataAire air-cooled air handling unit (DAAD-1034). Tag on adjacent disconnect reads, “CRAC_CH_02. Panel EM2 1,3,5” This unit has two separate refrigerant circuits served by an outdoor air-cooled condensing unit (DARC-1734) located on the west side of the building next to the generator approximately 100 feet away. Per conversations with DataAire, there is likely one single-point, 480V/3Ø power connection for the indoor unit (occasionally unit condensate pumps have a separate circuit, one was not observed), and one power connection for the outdoor unit (per panel schedule the outdoor unit is also fed from panelboard ‘EM2’ circuit 14,16,18).

b. (1) 16 year old, 16 Ton DataAire water-cooled air handling unit (DAWD series) with a single-point, 480V/3Ø, power connection. It was unverified where the power feed for this equipment is fed from (circuit labeling in panel EM2 does not reference this unit. Per conversations with facility personnel, the unit is provided with emergency power). Per conversations with Data Aire, this unit also has 2 compressors.

c. Both units supply air down into an underfloor plenum.

8. An air-cooled condensing unit for the 10Ton indoor unit is located outside the

building next to the generator on the west side.

9. Based on partial O&M information found in an envelope by one DataAire unit, a Nortec humidification system provides humidity to the space. The humidifier is installed within the air-cooled unit.

10. Routing of condensate drainage from the AHU’s and the humidifier was not

verified, although it is anticipated there are floor drains under the raised floor system which receive the discharge.

11. A work order (unverified) was also found on-site indicating that both units were

requested for remote-monitoring, switchover, modification, and troubleshooting through the existing Siemens APOGEE control system. It has not yet been verified if this work was completed.

12. The underfloor plenum distributes air from the cooling air handlers to floor

grilles adjacent the computer racks (on the cold side). The floor system is

approximately 20 years old and according to COWM IT personnel, the glues have started failing.

13. There are no exhaust systems installed in the space.

14. There is at least one 4-way louvered diffuser in the space. The equipment

supplying the diffuser was not verified; however it is believed that the diffuser provides ventilation air to the space from one of the local heat pump systems.

15. Emergency power is provided to both of the computer room air conditioners

through the building generator.

16. There is an Inergen, chemical suppression fire system with deterrent tanks in the room.

17. The primary building heating and cooling system is zoned heat pumps receiving

condenser water from a building loop. The building generally requires cooling the majority of the year when the sun is out. Return air from individual zones mixes in the plenums and mechanical room spaces creating unnecessary energy consumption through reheat/recool scenarios.

18. The overall reliability of the system is very high. Each unit has dual compressors

and circuiting to allow part load operation, and also meets the existing room load requirements by itself. By having one water-cooled unit and one air-cooled unit, there is a second system for heat rejection, should one heat rejection system fail.

19. No Construction Documents or record drawings were available to review for the

computer room systems, although original building drawings are available.

B. Capacity Analysis (Current and Future) 1. The only accurate way to determine the room’s required cooling capacity would

be by performing detailed survey of all the equipment for their rated capacities and perform a detailed load analysis. Detailed calculations like this are out of the scope of this project; however, we have estimated cooling loads via several methods explained below.

2. One way of estimating computer room load is to assume 50W Cooling/sq.ft. of room. With a 1,000sq.ft. room, this would be equal to 50kW, 170MBH, or 14.1 Tons.

3. Another way to estimate cooling load requirement is to allow 2 Tons

cooling/server rack and 1/2Ton cooling per distribution rack. Using this method, the city’s 6 server racks and 4 distribution racks, would equate to 14 Tons.

4. A third and perhaps most accurate way to estimate cooling load is to review the size of the UPS which powers the equipment than assume 85% of its rated

capacity as cooling load. With a 40 kVA UPS system, 85% converted to tons would equate to 9.7 Tons (peak capacity).

5. Based on these rules of thumb, an average rack power density of 1.7kW at the

time of site visit, and the fact that the room has cooled properly for many years with the 10 ton unit in operation, we estimate the current room peak load to be under 10 Tons with the average running load ½ of the peak (5 Tons).

6. With the storage capacity upgrades planned for the server room over the next

four years, we estimate the peak load could increase by another 4 Tons, with average loading of approximate 7 tons. For the purposes of estimating equipment upgrade options, we have assumed 12Ton equipment will be installed.

7. Given that load conditions can vary quickly as shifts towards cloud based computing and site based storage affect equipment in the room, we recommend loads be recalculated and long-term upgrade strategy be reassessed to confirm equipment sizing just prior to installations. Any equipment installed in the room should have multiple compressor staging or offloading capability.

8. With operating rack densities less than 2kW, the COWM server room is

considered to be low-density. Average server room density today is closer to 4kW/rack.

C. Cooling Systems for Data Centers 1. Three common characteristics exist for all Data Center cooling systems. They

are, system-type, air distribution type, and equipment location. These characterizations combine together to allow many possible configurations and systems for rooms, each with their own benefits and drawbacks.

2. Based on the possible combinations of system type, air distribution type, and equipment location, thirteen different system types may be used to cool a data room. Each system has an indoor component, a transport fluid, and an outdoor component. The figure below represents these 13 possible systems (source: Schneider Electric White Paper 59, Rev. 2, 2012).

Figure 1 – Data Room System Cooling Options

3. Air distribution is classified into three types as follows:

a. Flooded - traditional mixing of air within the space through air distribution inlets/outlets.

b. Targeted - Air is distributed within 10 feet of IT equipment intake and exhaust.

c. Contained - IT equipment supply and return air flow is completely enclosed to prevent mixing between the supply and return air streams.

4. Equipment layout falls within three categories.

a. Room-based – Equipment is designed to cool the room as a whole. b. Row-based – Equipment is arranged in a manner to provide cooling to

rows of racks or cabinets. c. Rack-based – Equipment is contained within or attached directly to

computer racks or cabinets.

5. Other important points to consider with data center HVAC design are: a. Fire, smoke, and water detection. b. Humidification/Dehumidification c. Economizing

6. Based on data HVAC classifications, the systems installed in the City of Westminster server room are classified as room-based, indoor air-cooled and water-cooled air conditioners with targeted supply, and flooded return.

D. Cooling System Options Evaluation for future upgrades. 1. In order to determine three viable system options for air-conditioning of the

server room, the thirteen possible systems were reviewed for their advantages, disadvantages, and typical uses (see Appendix A for an evaluation matrix). a. Any system which required the use of a chiller was not considered, as the

cost to add a chiller infrastructure is cost prohibitive and these chiller systems are typically only advantageous for very large data centers or whole buildings of which the data center is part.

b. A glycol-cooled system was discounted since the building does not currently use glycols, is not located in a cold environment, and would require additional types of maintenance and materials.

c. Air-ducted systems (including direct/indirect evaporative cooling and

rooftop units) were discounted from analysis for several reasons. The first is inadequate room in the existing plenum space for ductwork (anticipated to be 26”x26” for supply and return) between the computer room and the exterior without extensive modifications to existing building MEP systems. Additionally, there is little room available within screened areas outside the building for additional mechanical equipment, and air-driven systems are most cost-effective for larger data centers with higher power densities.

d. After discounting unrealistic systems, three types of systems are more

practical than others for conditioning of the existing space, air-cooled CRAC, water-cooled CRAC, and air-cooled self-contained (note the facility is currently using two of these systems).

2. Air-distribution strategy was considered separate from system type. Air

distribution is important to consider for maximizing cooling effectiveness, and lowering fan energy consumption (see Appendix A for an evaluation matrix). a. Contained supply/return air-strategies are not possible within the space

since the existing cooling equipment is installed in open racks. Contained strategies for supply or return would involve directly ducting supply and/or return air to equipment cabinets.

b. Targeted supply/return air distribution is valid for consideration as it is more effective than flooded strategies. Targeted supply strategy is suitable for cooling server rooms with densities of 6kW/rack or less, and is already in place with the raised floor system. In theory, it is possible to convert the existing room to a targeted return air path with a return duct over the hot aisle; however since there are two separate pieces of equipment that might be in operation, short cycling of return air from the plenum (which would reduce efficiency) is a concern. A targeted return

in addition to a targeted supply allows cooling for rack capacities up to 8kW a piece.

c. We do not recommend flooded supply strategies as they are the least

effective for cooling IT equipment and result in the greatest fan energy expenditure. The current space uses a flooded return strategy which does make sense in the current room due to separate pieces of cooling equipment.

3. Equipment layout was analyzed. A matrix is provided in Appendix A which discusses equipment layout pros and cons for a variety of evaluation criteria, as well as first costs, and energy use. Given the size and density of the COWM computer room, rack-based systems are not cost effective either from a first cost or an ongoing operating cost. Row-based layouts will not provide benefit with only one row of equipment. The only viable option for the size and layout of equipment in the space is room based cooling. Some reduction (approximately 10%) in annual operating costs may be possible by deploying hot aisle containment and targeted return air distribution; however it is anticipated the cost to install the ductwork needed for this will negate any operational savings.

4. Based on our assessment of available technologies, building limitations, equipment limitations, server room use and function, we have narrowed down system options to three viable strategies, which we believe will provide COWM the best value. These options are discussed in further detail below and as shown in Appendix B for comparative cost analysis. The systems studied include

a. Maintain existing strategy and equipment type (hybrid water-air cooled).

Only replace with 12Ton units in lieu of existing 10 ton and 16 ton.

b. Utilize (2) 12 ton, water-cooled computer room air conditioners with condensing water from the building’s condenser water loop.

c. Utilize (2) 12 ton air-cooled computer room air conditioning equipment.

E. Comparative System Analysis

1. Summary: Two different types of comparative analysis were conducted:

a. The differences between the proposed system and existing system

operating costs were calculated. Proposed system installation costs were compared against the projected operational cost savings (or increase) to identify the most economical value from an energy saving perspective.

b. The installation cost of each proposed system was also divided by its annual operating cost to identify the efficiency of the investment. The lower the number the lower the cost of the system relative to its energy consumption.

c. The summary of each analysis, presented in the order of system

recommendation is shown in the chart below. Refer to mathematical calculations in Appendix B for more information.

Table 1 – System Replacement Summary

2. First Costs: An estimate of cost was conducted for each system. Appendix B contains a more detailed breakdown of the installation costs of each system. Costs estimated included demoing/removing old equipment, wiring, piping, etc. Installation costs are based on engineering judgement, manufacturer pricing, and RS Means. Actual Contractor pricing for a designed system will vary from that shown here based on local, current market conditions at the time of construction.

3. Energy Costs: To calculate the energy costs of systems, the following assumptions were made:

(i) Room load is constant at 4.74 tons every hour of the year. This was the power draw of the UPS at the time of site review converted into tons.

(ii) Full load amperage at 480V/3phase was obtained for the existing and proposed equipment (manufactured by DataAire).

(iii) Since the existing and proposed equipment has two compressors, when satisfying average load conditions, only one compressor is needed, thus half the full load amperage was used to calculate power draw for the existing and proposed systems.

(iv) Equipment is subject to equal runtime. (v) Equipment normal service life is 25 years. (vi) Electricity costs $0.0379/kWh for consumption and $16.85/kW

for demand. For each system (existing and proposed), the power and cost was calculated using the operating amperage at 480Volt/3Phase. Additional power consumed by the humidifier was not considered in the comparative analysis since the existing and proposed systems humidification power draw would be nearly the same. The equipment power comparison and operational cost summary is shown in the two tables below:

First CostElec.

Operating Cost

Operational cost change

Payback (based on

energy savings)

Simple Payback (based on

energy use)Hybrid System $162,374 $14,897 $410 396.0 10.9

All Water-Cooled Equipment$147,136 $13,938 $1,369 107.5 10.6

All Air-Cooled Equipment $184,905 $15,856 -$549 N/A 11.7

System Replacement Summary

Table 2 – Equipment Power Summary

Table 3 – Operational Cost Summary

4. Maintenance Costs: For the purposes of comparison, maintenance is assumed to be the same for all systems. Air side systems have an outdoor piece of equipment to maintain which should cause them to have slightly more maintenance requirements. However, this additional cost is minimal compared to energy consumption.

Min. Ckt. Ampacity

Full Load Amps

Voltage / Phase

Power Draw (Watts)

16 Ton Water Cooled CU 63 52 480/3 52,37710 Ton Air cooled indoor 44 39 480/3 36,58110 ton air cooled outdoor 5.2 4.6 480/3 4,32312 ton water cooled 46 38 480/3 38,24412 ton air cooled indoor 51 45 480/3 42,40112 ton air cooled outdoor 7.5 6.9 480/3 6,235

Equip Summary

System Type

System Peak Power Water

System Peak

Power Air

kWh Used by Water Cooled

kWh Used by Air Cooled

Peak Demand

(kW)

kWh Cost

kW Cost

Total Cost

Current 43232 36248 94,678 79,384 43 $6,597 $8,710 $15,307Hybrid 31593 43149 69,188 94,496 43 $6,204 $8,694 $14,897All Water 31593 43149 138,376 43 $5,244 $8,694 $13,938All Air 31593 43149 188,992 43 $7,163 $8,694 $15,856

Operational Cost Summary

5. Discussion/Conclusions:

a. The existing equipment is in good condition, well-maintained, meets room load requirements, and appears to be in solid working order. We recommend maintaining the systems as long as possible, and only replacing equipment once major failure occurs. As there is two pieces of equipment, the facility will be able to maintain critical cooling (without backup) as upgrades occur, provided systems are replaced one at a time.

b. While the converting the room systems to two water-cooled cooling units appears marginally better, we do not recommend this strategy be utilized since both pieces of cooling equipment would be relying on the same system. Should catastrophic failure occur in the building’s condenser water system, the computer room would be without sufficient cooling. In addition, the addition of a second water-cooled unit would have to be more carefully coordinated and constructed to avoid downtime of the other water cooled unit.

c. We recommend the City of Westminster maintain existing strategy for

the computer room equipment with one piece of equipment water-cooled and the other air-cooled.

Appendix A

System Type Advantages Disadvantages Usually used inGenerally cost less, have fewer parts, and have greater heat removal capacity than CRAC units with the same footprint

Chilled water systems generally have the highest capital costs for installations below 100kW of electrical IT loads.

Chilled water system efficiency improves greatly with increased data center capacity Introduces an additional source of liquid into the IT environment.Chilled water piping loops are easily run very long distances and can service many IT environments (or whole building) from one chiller plantChilled water systems can be engineered to be extremely reliable.Can be combined with economizer modes of operation to increase efficiency. Designing the system to operate at higher water temps (54-59°F) will increase the

Keeps water away from IT equipment in chilled water applicationshigher first cost as a result of adding additional pumps and heat exchangers into the cooling system.

cooling systems that are closely coupled to the IT equipment for applications like row and rack based

Oil-less refrigerants and non-conductive fluids eliminate risk of mess or damage to servers in the event of a leak.

Chip level cooling where coolant is piped directly to the server.

Efficiency of cooling system due to close proximity to servers or direct to chip level.

Lowest overall cost

Refrigerant piping must be installed in the field. Only properly engineered piping systems that carefully consider the distance and change in height between the IT and outdoor environments will deliver reliable performance

Easiest to Maintain Refrigerant piping cannot be run long distances reliably or economically.Multiple computer room air conditioners cannot be attached to a single air cooled condenser.

The entire refrigeration cycle is contained inside the CRAC unit as a factory-sealed andtested system for highest reliability with the same floor space requirements as a two piece air-cooled system

Additional required components (pump package, valves) raise capital and installation costs when compared with air-cooled DX systems.

Glycol pipes can run much longer distances than refrigerant lines (air-cooled split system) and can service several CRAC units from one dry cooler and pump package. Maintenance of glycol volume and quality within the system is required.In cold locations, the glycol within the dry cooler can be cooled so much (below 50°F), that it can bypass the heat exchanger in the CRAC unit and flow directly to a specially installed economizer coil. Under these conditions, the rerigeration cycle is turned off and the air that flows through the economizer coil, now filled with cold flowing glycol, cools the IT environment. This economizer mode, also known as "free cooling", provides excellent operating cost reductions when used. Introduces an additional source of liquid into the IT environmentAll refrigeration cycle components are contained inside the computer room air conditioning unit as a factory-sealed and tested system for highest reliability High initial cost for cooling tower, pump and piping systems.Condenser water piping loops are easily run long distances and almost always service many computer room air conditioning units nd other devices from one cooling tower.

Very high maintenance costs due to frequent cleaning and water treatment requirements

In leased IT environments, usage of the buildng's condenser water is generally less expensive than chilled water Introduces an additional source of liquid into the IT environment

A non-dedicated cooling tower may be less reliable than a cooling tower dedicated to the computer room air conditioner.

Has the lowest installation cost. There is nothing to install on the roof or outside the building except for the condenser air outlet. Less heat removal capacity per unit compared to other configurations

In wiring closets, laboratory environments, and computer rooms with moderate availability

All refrigeration cycle components are contained inside the computer room air conditioning unit as a factory-sealed and tested system for highest reliability

Air routed into and out of the IT environment for the condensing coil usually requires ductwork and/or dropped ceiling. Sometimes used to fix hotspots in data centers

Some systems can rely on the building HVAC system to reject heat. Issues can arise when the building HVAC system shuts down in the evening or over the weekend.

All cooling equipment is placed outside the data center, allowing for white space to be fully utilized for IT equipment May be difficult to retrofit into an existing data center

In 1000kW data centers and larger with high power density.

Significant cooling energy savings in dry climates (e.g.75%) compared to systems with no economizer mode. Subject to frequent filter changes in locations with poor air quality

Evaporative cooling contributes to humidity in the data center.All cooling equipment is placed outside the data center, allwing for white space to be fully utilized for IT equipment May be difficult to retrofit into an existing data center.

In 1000kW data centers and larger with high power density.

Significant cooling energy savings in most climates (e.g.75%) compared to systems with no economizer mode.All cooling equipment is placed outside the data center, allowing for white space to be fully utilized for IT equipment May be difficult to retrofit into an existing data center In data centers that are part of a mixed facilityeconomizer mode

Water-Cooled CRACIn conjunction with other building systems in data centers 30kW and larger with moderate-to-high

availability requirements

Air-Cooled Self Contained

Direct Fresh air evaporative cooling

system

Indirect Air Evaporative Cooling

System

Self-contained rooftop system

CRAH

Data centers 200kW and larger with moderate to high availability requirements or as a high

availability dedicated solution. Water-cooled chilled water systems are often used to cool entire

buildings where the data center may ne only a small part

Pumped refrigerant heat exchanger

Air-Cooled CRACIn wiring closers, computer rooms, and 7-200kW

data centers with moderate availability requirements

Glycol-Cooled CRAC In computer rooms and 30-1,000kW data centers with moderate availability requirements.

Supply Style Return Style Comments Uses/Recommendations Drawing

Low cost, simple installation

Least energy efficient of all air distribution strategies because 100% of the cold supply air is allowed to mix with the hot return air.

Supply air temperature can be unpredictable

Targeted Flooded More energy efficient than flooded supply since more IT equipment hot exhaust air diverted back to the cooling unit

Not recommended for new designs -unable to keep up with modern power

densities. Can cool up to 6kW per rack

Low cost, easy to install

More efficient than flooded return since 40-70% of IT hot exhaust air is captured andelivered back to the cooling unit.

Supply air is more predictable than flooded supply since less hot air is allowed to mwith cold supply air.

More energy efficient than targeted supply but less efficient than contained return.

Containing the suppply air forces the rest of the room to become the hot aisle which limits the number of economizer hours.

Supply air is more predictable since little hot air is allowed to mix with cold supply air.

More energy efficient than flooded return since 60-80% of IT equipment hot exhaust air is captured and delivered back to the cooling unit.

Supply air more predictable since less hot air is allowed to mix with cold supply air.

Upgradeable (vendor specific)

Most energy efficient of all air distribution strategies since it allows increase cooling unit supply temp resulting in increased economizer hours.70-100% of IT equipment hot exhaust air is captured and delivered back to the cooling unit.

Supply air is most predictable since no hot air is allowed to mix with cold supply air.

More efficient than targeted supply but less efficient than contained return.

Containing the supply air forces the rest of the room to become the hot aisle which limits the number of economizer hours.


Upgradeable (vendor specific)

More efficient than targeted supply and return since 70-100% of IT equipment hot exhaust air is captured and delivered back to the cooling unit.


Allows increased cooling unit supply temperature resulting in increased economizer hours.

Slightly less efficient than contained return with flooded or targeted supply - (due to increased fan energy)

Allows increased cooling unit supply temp resultin in increased economizer hours.

Contained Targeted

Targeted Contained Hot Spot Problem Solver. Can cool up to 30kW per rack.

Contained Contained Harsh non-data center environments. Up to 30kW per rack.

Mainframes / racks with vertical airflow.Can cool up to 30kW per rack

Mainframes/racks with vertical airflow. Can cool up to 30kW per rack.

Targeted Targeted Small to medium data centers. Can cool up to 8kW per rack

Flooded Contained Large data center / colocation. Can cool up to 30kW per rack

Contained Flooded

Traditional Implementations

Flooded FloodedSmall LAN rooms < 40kW, Not

recommended for most data centers. Can cool up to 3kW per rack.

Flooded Targeted Not recommended for most data centers. Can cool up to 6kW per rack.

Hard floor, cooling unit outdoors

Not effective because air mixing prevents predicatble IT inlet temperatures

Targeted Flooded No non-traditional alternative

Hard floor, cooling unit located outdoors

Not effective because air mixing prevents predictable IT inlet temperatures

Raised floor, perimeter cooling units

Good solution for existing data centers

Variable speed fans on cooling unts controlled by pressure and active tiles controlleby IT temperature

Hard-floor, row based cooling units

Variable speed fans on cooling units controlled by IT temperature

Hard floor, cooling unit located outdoors

variable speed fans on cooling units controlled by IT temperature

Raised floor, cooling unit located outdoors

Targeted return does not add much value since supply is contained therefore not recommended.Variable speed fans on cooling units controlled by pressure and active tiles controlled by IT temperature

Hard floor, row-based cooling units


Hard floor, row-based cooling units


In general distribution strategies are presented in order of cost increase within each category (traditional and non-traditional)Data centers with clusters of high power density and low power density cabinets, may employ a combination of strategies.

Targeted Contained Recommended for data centers below 1MW.

Contained Contained

Only recommended for harsh environments or existing data centers

where complete containment is required for a single row of rack

Flooded Contained recommended for new data centers

Contained Targeted not recommended

Contained Flooded Not recommended for new data centers.

Targeted Targeted Recommended for data centers below 1MW.

Non-traditional implementations

Flooded Flooded Not recommended for most data centers.

Flooded Targeted Not recommended for most data centers.

Equipment Layout MatrixRoom-Based Row-Based Rack-Based

ProsQuickly to change cooling distribution pattern for power density < 3kW

Easy to plan for any power density; cooling capacity can be shared.

Easy to plan for any power density; isolated from the existing cooling system.

ConsLess efficient when not containing the whole space Requires hot and cold aisle layout. Cooling capacity can't be shared with other

racks.

Pros

Redundant units can be shared across all racks in the data center

Redundant units can be shared scross multiple racks in a pod; close coupling eliminates vertical temperature gradients.

Close coupling eliminates hot spots and vertical temperature gradients; standardized solutions minimize human error

ConsContainment required to separate the air streams. Redundancy required for each pod of racks. Redundancy required for each rack

ProsEasy to Reconfigure perforated floor tiles Ability to match the cooling requirements; planning and

engineering can be eliminated or reduced

Pre-engineered system and standardized components eliminates or reduced planning and engineering

Cons

Air delivery dictates oversized capacity; pressure requirements for under floor delivery area are a function of the room size and floor depth.

First cost of this approach can be higher as the size of the data center increases

Cooling system will likely be oversized and capacity will be wasted which can drive up first cost.

Pros

Cooling equipment is placed on the perimeter or outside the room keeping technicians further away from IT equipment

Modular components reduced downtime; standardized components reduce the technical expertise

Standardized components reduce the technical expertise; in-house staff can perform routine service procedures.

ConsRequires trained technician or experts to perform service

Cooling equipment I splaced in the row where technicians will be working alongside IT equipment

2N redundancy required for concurrent system repair and maintenace

ProsLarger systems simplify the numper of points to connect to and manage.

Easy to navigate through menu interface ablte to provide near predictive failure analysis

Easy to navigate through menu interface and able to provide predictive failure analysis

ConsRequire advanced service training; difficult to provide real-time analysis.

For large deployments requires many points of connectivity.

For large deployments requires many points of connectivity.

Lowest first cost. Fewer units/piping. Cost decreases slightly as rack power density increases assuming a smaller room footprint. Hot aisle containment, while good for cooling efficiency, will also slightly increase first cost.

Slightly higher than room. More units/piping. Cost decreases as rack power density increase assuming reduced footprint/unit quantity.

Much higher at lower power rack densities. As density increases, first cost improves dramaticall to a point, then increases again as rack capacity is maximized and the rack equipment fans operate a full capacities.

Data Center Assumptions 480kW IT load; Weather location - St. Louis MO; 120cfm/kW rack; equipment rated to 125% capacity for room based without hot aisle containment; RS Means cost data for piping; $0.15/kWh; No redundancy

Highest due to most fan energy and least effective distribution. Cost can be reduced by using hot aisle containment.

Consistenly lower than room based cooling Higher at low densities.

Data Center Assumptions 480kW IT load; Weather location - St. Louis MO; 120cfm/kW rack; equipment rated to 125% capacity for room based without hot aisle containment; RS Means cost data for piping; $0.15/kWh; No redundancy

Cost advantage at low densities. Can be difficult in high-density environments.

Significant penalty at 1-2kW per rack. However for higher density this penalty is eliminated up to 25kW. Key benefit to row-based cooling

Only way to provide redundancy is with an additional CRAH per rack. For isolated high density racks, this can be effective.

Water Piping or other piping near IT equipment

High density data centers with multiple CRAH generally use a chilled water cooling system for environmental and cost concerns. Refrigerants have less of a possibility of damaging IT equipment, but are generally more costly

Redundancy

System Availability

Life Cycle Cost (TCO)

Serviceability

Manageability

First Cost

Electrical Efficiency

Agility

Appendix B

Project Name City of Westminster Server RoomProject number 9599.00Date: 19‐May‐15By: WGP

Base Design ‐ Replace with Similar Equipment

PLUMBING NO. UNITS UNIT PER UNIT TOTAL PER UNIT TOTAL Line Item Subtotals

Plumbing Demo 1 LOT 200.00$ 200.00$ ‐$ 200.00$ Solder 1 EA ‐$ 6.85$ 6.85$ 6.85$ 1‐1/2" closed cell cellular, ASJ, sealant 10 LF 5.80$ 58.00$ 8.70$ 87.00$ 145.00$ 3/4 Type L Copper, couplings, hanger 10 LF 6.50$ 65.00$ 5.85$ 58.50$ 123.50$ Humidifier 1 EA 163.00$ 163.00$ 2,850.00$ 2,850.00$ 3,013.00$ 1/2" Type L CU, couplings 10 LF 5.50$ 55.00$ 4.24$ 42.40$ 97.40$

HVAC Demo 1 LOT 3,352.00$ 3,352.00$ ‐$ 3,352.00$ Misc. Valves, Gauges, etc. 4 EA 28.00$ 112.00$ 45.00$ 180.00$ 292.00$ Test Adjust & Balance 1 LOT 2,500.00$ 2,500.00$ ‐$ ‐$ 2,500.00$ Instrumentation and Control 1 LOT 8,000.00$ 8,000.00$ ‐$ 8,000.00$ Water‐Cooled Indoor Unit, 16T 0 EA 3,015.00$ ‐$ 38,900.00$ ‐$ ‐$ Air‐Cooled Indoor/Outdoor Unit, 10T 0 EA 3,275.00$ ‐$ 36,900.00$ ‐$ ‐$ Water Cooled Indoor, 12T 1 EA 2,825.00$ 2,825.00$ 36,000.00$ 36,000.00$ 38,825.00$ Air‐Cooled Indoor/Outdoor, 12T 1 EA 3,400.00$ 3,400.00$ 38,200.00$ 38,200.00$ 41,600.00$ 1‐1/2" Type L CU 10 LF 8.60$ 86.00$ 17.55$ 175.50$ 261.50$ 1" insulation for 1‐1/2, CaSi with cover 10 LF 4.34$ 43.40$ 3.35$ 33.50$ 76.90$ 1‐3/8" ACR, coupling, hangers 200 LF 4.53$ 906.00$ 11.85$ 2,370.00$ 3,276.00$ 7/8" ACR, couplings, hangers 200 LF 3.49$ 698.00$ 6.05$ 1,210.00$ 1,908.00$ 1‐1/2" control valve 1 EA 38.50$ 38.50$ 615.00$ 615.00$ 653.50$ 1‐1/2" closed cell cellular, ASJ, sealant 200 LF 5.80$ 1,160.00$ 8.70$ 1,740.00$ 2,900.00$

Demolition 1 LOT 1,500.00$ 1,500.00$ ‐$ 1,500.00$ 5HP, 480/3 motor connection 2 EA 9.00$ 18.00$ 52.50$ 105.00$ 123.00$ 5HP, motor starter 2 EA 182.00$ 364.00$ 243.00$ 486.00$ 850.00$ #6 Wiring 4.5 CLF 63.00$ 283.50$ 64.00$ 288.00$ 571.50$ #10 Wiring 1.5 CLF 42.00$ 63.00$ 22.50$ 33.75$ 96.75$ 1" Metal conduit 150 LF 3.65$ 547.50$ 1.69$ 253.50$ 801.00$ 60A Disconnect 3 EA 150.00$ 450.00$ 585.00$ 1,755.00$ 2,205.00$ Breakers 3 EA 120.00$ 360.00$ 221.00$ 663.00$ 1,023.00$

Labor Sub‐Total 27,247.90$

Material Sub‐Total 87,153.00$ 114,400.90$ Subtotal

Labor Factor @ 22% 5,994.54$

Material Mark‐Up @ 10% 8,715.30$ 14,709.84$

Markup

129,110.74$ Subtotal with

Markup

Overhead @

11% 14,202.18$ 143,312.92$ Subtotal with overhead

Profit @10% 14,331.29$ 157,644.21$ Subtotal with

profitBond @ 3% 4,729.33$ 162,373.54$ Est.

General

HVAC

Eletrical

Plumbing

QUANTITY LABOR MATERIAL


Replace with water‐cooled equipment



HVAC Demo 1 LOT 3,352.00$ 3,352.00$ ‐$ 3,352.00$ Misc. Valves, Gauges, etc. 8 EA 28.00$ 224.00$ 45.00$ 360.00$ 584.00$ Test Adjust & Balance 1 LOT 2,500.00$ 2,500.00$ ‐$ ‐$ 2,500.00$ Instrumentation and Control 1 LOT 8,000.00$ 8,000.00$ ‐$ 8,000.00$ Water‐Cooled Indoor Unit, 16T 0 EA 3,015.00$ ‐$ 38,900.00$ ‐$ ‐$ Air‐Cooled Indoor/Outdoor Unit, 10T 0 EA 3,275.00$ ‐$ 36,900.00$ ‐$ ‐$ Water Cooled Indoor, 12T 2 EA 2,825.00$ 5,650.00$ 36,000.00$ 72,000.00$ 77,650.00$ Air‐Cooled Indoor/Outdoor, 12T 0 EA 3,400.00$ ‐$ 38,200.00$ ‐$ ‐$ 1‐1/2" Type L CU 20 LF 8.60$ 172.00$ 17.55$ 351.00$ 523.00$ 1" insulation for 1‐1/2, CaSi with cover 20 LF 4.34$ 86.80$ 3.35$ 67.00$ 153.80$ 1‐3/8" ACR, coupling, hangers 0 LF 4.53$ ‐$ 11.85$ ‐$ ‐$ 7/8" ACR, couplings, hangers 0 LF 3.49$ ‐$ 6.05$ ‐$ ‐$ 1‐1/2" control valve 2 EA 38.50$ 77.00$ 615.00$ 1,230.00$ 1,307.00$ 1‐1/2" closed cell cellular, ASJ, sealant 0 LF 5.80$ ‐$ 8.70$ ‐$ ‐$

Demolition 1 LOT 1,500.00$ 1,500.00$ ‐$ 1,500.00$ 5HP, 480/3 motor connection 2 EA 9.00$ 18.00$ 52.50$ 105.00$ 123.00$ 5HP, motor starter 2 EA 182.00$ 364.00$ 243.00$ 486.00$ 850.00$ #6 Wiring 4.5 CLF 63.00$ 283.50$ 64.00$ 288.00$ 571.50$ #10 Wiring 1.5 CLF 42.00$ 63.00$ 22.50$ 33.75$ 96.75$ 1" Metal conduit 150 LF 3.65$ 547.50$ 1.69$ 253.50$ 801.00$ 60A Disconnect 2 EA 150.00$ 300.00$ 585.00$ 1,170.00$ 1,470.00$ Breakers 2 EA 120.00$ 240.00$ 221.00$ 442.00$ 682.00$



Labor Factor @ 22% 5,262.14$

Material Mark‐Up @ 10% 7,983.10$ 13,245.24$ Markup


Markup

Overhead @



profit

Bond @ 3% 4,285.53$ 147,136.47$

Estimated

Total

Eletrical


General

Plumbing

HVAC


Replace with air‐cooled equipment


Building Site Work 1 LOT $2,500 2,500.00$ $2,500 2,500.00$ 5,000.00$


HVAC Demo 1 LOT 3,352.00$ 3,352.00$ ‐$ 3,352.00$ Misc. Valves, Gauges, etc. 0 EA 28.00$ ‐$ 45.00$ ‐$ ‐$ Test Adjust & Balance 1 LOT 2,500.00$ 2,500.00$ ‐$ ‐$ 2,500.00$ Instrumentation and Control 1 LOT 8,000.00$ 8,000.00$ ‐$ 8,000.00$ Water‐Cooled Indoor Unit, 16T 0 EA 3,015.00$ ‐$ 38,900.00$ ‐$ ‐$ Air‐Cooled Indoor/Outdoor Unit, 10T 0 EA 3,275.00$ ‐$ 36,900.00$ ‐$ ‐$ Water Cooled Indoor, 12T EA 2,825.00$ ‐$ 36,000.00$ ‐$ ‐$ Air‐Cooled Indoor/Outdoor, 12T 2 EA 3,400.00$ 6,800.00$ 38,200.00$ 76,400.00$ 83,200.00$ 1‐1/2" Type L CU 0 LF 8.60$ ‐$ 17.55$ ‐$ ‐$ 1" insulation for 1‐1/2, CaSi with cover 0 LF 4.34$ ‐$ 3.35$ ‐$ ‐$ 1‐3/8" ACR, coupling, hangers 400 LF 4.53$ 1,812.00$ 11.85$ 4,740.00$ 6,552.00$ 7/8" ACR, couplings, hangers 400 LF 3.49$ 1,396.00$ 6.05$ 2,420.00$ 3,816.00$ 1‐1/2" control valve 0 EA 38.50$ ‐$ 615.00$ ‐$ ‐$ 1‐1/2" closed cell cellular, ASJ, sealant 400 LF 5.80$ 2,320.00$ 8.70$ 3,480.00$ 5,800.00$

Demolition 1 LOT 1,500.00$ 1,500.00$ ‐$ 1,500.00$ 5HP, 480/3 motor connection 2 EA 9.00$ 18.00$ 52.50$ 105.00$ 123.00$ 5HP, motor starter 2 EA 182.00$ 364.00$ 243.00$ 486.00$ 850.00$ #6 Wiring 4.5 CLF 63.00$ 283.50$ 64.00$ 288.00$ 571.50$ #10 Wiring 1.5 CLF 42.00$ 63.00$ 22.50$ 33.75$ 96.75$ 1" Metal conduit 150 LF 3.65$ 547.50$ 1.69$ 253.50$ 801.00$ 60A Disconnect 4 EA 150.00$ 600.00$ 585.00$ 2,340.00$ 2,940.00$ Breakers 4 EA 120.00$ 480.00$ 221.00$ 884.00$ 1,364.00$



Labor Factor @ 22% 7,276.94$

Material Mark‐Up @ 10% 9,697.50$ 16,974.44$

Markup


Markup

Overhead @



profitBond @ 3% 5,385.58$ 184,904.86$ Est.

Eletrical


General

Plumbing

HVAC

Exising Compared to Hybrid-Cooled Existing Compared to Water-Cooled Existing Compared to Air-Cooled0% Minimum Rate of Return 0% Minimum Rate of Return 0% Minimum Rate of Return25 Investment Life 25 Investment Life 25 Investment Life

0% Energy Escalation Factor 0% Energy Escalation Factor 0% Energy Escalation FactorNo Change Change No Change Change No Change Change

First Cost $0 $162,374 First Cost $0 $147,136 First Cost $0 $184,905Initial Annual Electricity Cost $410 $0 Initial Annual Electricity Cost $1,369 $0 Initial Annual Electricity Cost $0 $549P/A' - GPW Factor 24.9968 24.9968 P/A' - GPW Factor 24.9968 24.9968 P/A' - GPW Factor 24.9968 24.9968Present Energy Value $10,251 $0 Present Energy Value $34,227 $0 Present Energy Value $0 $13,726Present Worth(Cost) $10,251 $162,374 Present Worth(Cost) $34,227 $147,136 Present Worth(Cost) $0 $198,630

First Cost $0 $162,374 First Cost $0 $147,136 First Cost $0 $184,905A/P Factor 0.0400 0.0400 A/P Factor 0.0400 0.0400 A/P Factor 0.0400 0.0400Annual First Cost $0 $6,496 Annual First Cost $0 $5,886 Annual First Cost $0 $7,397Initial Annual energy Cost $410 $0 Initial Annual energy Cost $1,369 $0 Initial Annual energy Cost $0 $549A/A' Factor 1.0000 1.0000 A/A' Factor 1.0000 1.0000 A/A' Factor 1.0000 1.0000Annual Energy Cost $410 $0 Annual Energy Cost $1,369 $0 Annual Energy Cost $0 $549Annual Cost $410 $6,496 Annual Cost $1,369 $5,886 Annual Cost $0 $7,946

Initial Energy Savings $410 Initial Energy Savings $1,369 Initial Energy Savings -$549Initial investment $162,374 Initial investment $147,136 Initial investment $184,905Simple Payback Years 396.0 Simple Payback Years 107.5 Simple Payback Years N/A

Present Worth Allocation Present Worth Allocation

Annual Cost Allocation Annual Cost Allocation

Payback Payback

Present Worth Allocation

Annual Cost Allocation

Payback

Hybrid compared vs. its Energy Consumption Air-Cooled vs. its Energy Consumption Water Cooled vs. its energy Consumption0% Minimum Rate of Return 0% Minimum Rate of Return 0% Minimum Rate of Return25 Investment Life 25 Investment Life 25 Investment Life

0% Energy Escalation Factor 0% Energy Escalation Factor 0% Energy Escalation FactorNo Change Change No Change Change No Change Change

First Cost $0 $162,374 First Cost $0 $184,905 First Cost $0 $147,136Initial Annual Electricity Cost $14,897 $0 Initial Annual Electricity Cost $15,856 $0 Initial Annual Electricity Cost $13,938 $0P/A' - GPW Factor 24.9968 24.9968 P/A' - GPW Factor 24.9968 24.9968 P/A' - GPW Factor 24.9968 24.9968Present Energy Value $372,377 $0 Present Energy Value $396,359 $0 Present Energy Value $348,406 $0Present Worth(Cost) $372,377 $162,374 Present Worth(Cost) $396,359 $184,905 Present Worth(Cost) $348,406 $147,136

First Cost $0 $162,374 First Cost $0 $184,905 First Cost $0 $147,136A/P Factor 0.0400 0.0400 A/P Factor 0.0400 0.0400 A/P Factor 0.0400 0.0400Annual First Cost $0 $6,496 Annual First Cost $0 $7,397 Annual First Cost $0 $5,886Initial Annual energy Cost $14,897 $0 Initial Annual energy Cost $15,856 $0 Initial Annual energy Cost $13,938 $0A/A' Factor 1.0000 1.0000 A/A' Factor 1.0000 1.0000 A/A' Factor 1.0000 1.0000Annual Energy Cost $14,897 $0 Annual Energy Cost $15,856 $0 Annual Energy Cost $13,938 $0Annual Cost $14,897 $6,496 Annual Cost $15,856 $7,397 Annual Cost $13,938 $5,886

Initial Energy Savings $14,897 Initial Energy Savings $15,856 Initial Energy Savings $13,938Initial investment $162,374 Initial investment $184,905 Initial investment $147,136Simple Payback Years 10.9 Simple Payback Years 11.7 Simple Payback Years 10.6

Present Worth Allocation

Annual Cost Allocation

Payback

Present Worth Allocation Present Worth Allocation

Annual Cost Allocation Annual Cost Allocation

Payback Payback