PURPOSE OF STUDY
The purpose of the study was to establish the ability of the existing electrical and mechanical systems infrastructure to support the current and future campus electrical and HVAC loads. To establish these criteria an assessment of the office space and data center loads was conducted. A matrix (table 7) was compiled that listed both current and projected loads by space type.
Details of the assessment study can be found in the "Due Diligence" section of this report.
EXECUTIVE SUMMARY
The study has established that the electrical and mechanical infrastructure cannot support the future or current demands of the campus. This study lists infrastructure upgrades for consideration that will upgrade the campus M&E infrastructure to levels commensurate with the campus demands.
MECHANICAL SYSTEM
Current System Laboratory Loads
The laboratory loads have been projected to increase in the future. The quantities in kilowatts (kW) are listed below.
Building Existing Laboratory Loads (kW)
Building A 331
Building B 478
Building C 1,262
Building D 37
Total 2,108
Building Projected Laboratory Loads (kW)
Building A 2,018
Building B 2,900
Building C 5,626
Building D 592
Total 11,136
HVAC System Upgrades
Option #1 – Baseline Model
This option increases the existing air-cooled chiller capacity to support the increase in electrical equipment load. This option also replaces the air-cooled DX roof mounted AHU's with chilled-water AHU’s. It is assumed that all DX equipment will be replaced with chilled water equipment, including replacing the existing DX units in IDF rooms with fan coil units.
The Table 1 below shows the energy consumed by the HVAC system for this option. The table is split to show the HVAC system power required to condition loads that operate 24/7 (electric rooms, IDF, labs), and power required to condition general office loads.
Table 1. Projected HVAC Systems Power Input (kW) – Air Cooled Chiller
Building Projected Office Power (kW) Projected 24/7 Power (kW) Total Projected Power (kW)
Building A 109 21 138
Building B 158 992 1,232
Building C 266 1,423 2,104
Building D 109 25 125
Total 640 2,960 3,600
Pros
1. Least expensive first cost.
Cons
1. Much more expensive energy /operational costs than all other options
2. No central control.
3. No system operation diversity.
4. Equipment has shortest life span of all options.
5. Equipment exposed to weather.
6. Highest maintenance of all options.
7. Roof locations means not as easy to maintain as central plant equipment.
8. Not easily expandable for future load increases.
9. HVAC equipment has the highest electrical demand of all of the options and will result in the largest electrical service increase.
10. No energy rebates available
Option #2 – Cooling Tower Chilled-Water Central Plant
A central plant with high efficiency water-cooled chillers and cooling towers with variable frequency drives sized to support all cooling loads. Chilled water will be distributed to new high efficiency VAV roof mounted AHU's and to fan coil units throughout the buildings.
Table 2 below shows the energy consumed by the HVAC system for this option.
Table 2. Projected HVAC Systems Power Input (kW) – Cooling Tower Chilled-Water Plant
Building Projected Office Power (kW) Projected 24/7 Power (kW) Total Projected Power (kW)
Building A 109 30 138
Building B 44 106 149
Building C 60 185 245
Building D 109 17 125
Power Plant 425 1,319 1,743
Total 745 1,656 2,401
Pros
1. Much more energy efficient than option #1 (baseline)
2. Easily expandable for future load increases.
3. Central plant Energy Management System (EMS) provides overall campus control & efficiency
4. Equipment in central plant much easier to maintain than option #1
5. Equipment has longer life expectancy (30 years vs. 15 years) than option #1
6. Central plant system provides diversity improving energy consumption and redundancy.
7. Smaller HVAC electrical demand than option#1
8. Qualifies for energy rebate.
9. Provides opportunity for “free” cooling with water side economizer
Cons
1. More expensive first cost than option #1
Option #3 – 100% Geothermal Chilled-Water Central Plant
A central plant with high efficiency water-cooled VFD chillers with geothermal bores sized to support all campus loads, (no cooling towers). Chilled water will be distributed to new high efficiency VAV roof mounted AHU's and fan coil units throughout the buildings.
Table 3 below shows the energy consumed by the HVAC system for this option.
Table 3. Projected HVAC Systems Power Input (kW) – 100% Geothermal Chilled-Water Plant
Building Projected Office Power (kW) Projected 24/7 Power (kW) Total Projected Power (kW)
Building A 109 30 138
Building B 44 106 149
Building C 60 185 245
Building D 109 17 125
Power Plant 231 717 948
Total 551 1,055 1,606
Pros
1. Much more energy efficient than option #1 (baseline) & option #2
2. Easily expandable for future load increases.
3. Central plant Energy Management System (EMS) provides overall campus control & efficiency
4. Equipment in central plant much easier to maintain than option #1, #2 & #4
5. Equipment has longer life expectancy (30 – 50 years vs. 15 years) than option #1, #2 & #4.
6. Geothermal water is cooler than cooling tower water, lowering chiller head pressure, greatly increasing energy efficiency and extending operating life more than all other options.
7. Central plant system provides diversity improving energy consumption and redundancy, best of all options.
8. Smallest HVAC electrical demand of all options resulting in the smallest electrical service of all options.
9. Uses most renewable energy of all options.
10. No water is evaporated via cooling towers.
11. Water savings of 10,800,000 gallons per year over option #2.
12. Most LEED points in energy & atmosphere and water efficiency sections.
13. Highest energy rebate of all options.
Cons
1. First cost highest of all options.
Option #4 – Geothermal Hybrid Chilled Water Central Plant
A central plant with high efficiency water-cooled VFD chillers with geothermal bores sized to support all 24/7 loads, and cooling towers with variable frequency drives to support all non 24/7 cooling loads. Chilled water will be distributed to new high efficiency VAV roof mounted AHU's and fan coil units throughout the buildings.
Table 4 below shows the energy consumed by the HVAC system for this option.
Table 4. Projected HVAC Systems Power Input (kW) – Geothermal Hybrid Chilled-Water Plant
Building Projected Office Power (kW) Projected 24/7 Power (kW) Total Projected Power (kW)
Building A 109 30 138
Building B 44 106 149
Building C 60 185 245
Building D 109 17 125
Power Plant 425 717 1,142
Total 745 1,055 1,800
Pros
1. Much more energy efficient than option #1 (baseline) & option #2
2. Easily expandable for future load increases.
3. Central plant Energy Management System (EMS) provides overall campus control & efficiency
4. Equipment in central plant much easier to maintain than option #1
5. Equipment has longer life expectancy (30 – 50years vs. 15 years) than option #1 & option #2.
6. Geothermal water is cooler than cooling tower water, lowering chiller head pressure, greatly increasing energy efficiency and extending operating life more than all other options.
7. Central plant system provides diversity improving energy consumption and redundancy.
8. Smaller HVAC electrical demand than option#1 & option #2.
9. Uses renewable energy.
10. Significantly reduces water consumption.
11. Increased number of LEED points.
12. Higher energy rebate than option #1 & #2
Cons
1. First cost higher than option #1 & #2
2. Cooling tower use wastes more water than option #3.
Life Cycle Cost Analysis
Following is a life cycle costs analysis comparing all 4 options. The second table compares the option with no federal tax depreciation and no savings by design rebate.
ELECTRICAL SYSTEM
Current System Load Analysis
The existing electrical services are currently overloaded. Refer to appendices A1 through D1. Below is the representation of the appendix in percentage.
• Building A: 65% overloaded
• Building B: 16% overloaded
• Building C:
o Switchboard "C-SB1": 21% overloaded
o Switchboard "C-SB2": 4% overloaded
• Building D: 32% overloaded
Projected Load Increase – short term (equipment only)
The numbers below is based on the information provided by Symantec.
• Building A: 34% projected load increase
• Building B: 18% projected load increase
• Building C:
o Switchboard "C-SB1": 20% projected load increase
o Switchboard "C-SB2": 38% projected load increase
• Building D: 22% projected load increase
Potential Load Increase – long term (equipment only)
For the longer term, a minimum of 10% was added for potential long term load increase.
• Building A: 13% projected additional load increase in the long term
• Building B: 12% projected additional load increase in the long term
• Building C:
o Switchboard "C-SB1": 12% projected additional load increase in the long term
o Switchboard "C-SB2": 14% projected additional load increase in the long term
• Building D: 12% projected additional load increase in the long term
HVAC Replacement Option # 0 (baseline model)
Pros:
1. Least expensive first cost.
• No Central Plant so only 5 electric service upgrades versus 6 new services that includes the Central Plant.
• Less electrical equipments needed.
• Less power distribution system needed.
Cons:
1. Much more expensive energy and operational costs than all other options.
HVAC Replacement Option # 1 (Chilled Water Central Plant)
Pros:
1. 33% less energy consumption from HVAC system than the baseline model.
2. A little less on PG&E costs than the baseline model.
3. Power service equipments may be located in the Central Plant.
4. Less costly on the power distribution side of the costs.
Cons:
1. More electrical equipments required.
HVAC Replacement Option # 2 (100% Geothermal Chilled Water Central Plant)
Pros:
1. 55% less energy consumption from HVAC system than the baseline model.
2. A little less on PG&E costs than the baseline model.
3. Power service equipments may be located in the Central Plant.
4. Less costly on the building power distribution side of the costs.
Cons:
1. More electrical equipments required.
2. Some cost added for site trenching to power the sump pumps in the geothermal vaults.
HVAC Replacement Option # 3 (Hybrid Geothermal Chilled Water Central Plant)
Pros:
1. 50% less energy consumption from HVAC system than the baseline model.
2. A little less on PG&E costs than the baseline model.
3. Power service equipments may be located in the Central Plant.
4. Less costly on the building power distribution side of the costs.
Cons:
1. More electrical equipments required.
2. Some cost added for site trenching to power the sump pumps in the geothermal vaults.
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