Newsletter | Infrastructure Study + 1 post(s)

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Infrastructure Study Posted: 26 Oct 2015 07:40 PM PDT 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. The post Infrastructure Study appeared first on Poltrona.

A Geothermal Feasibility Guide Posted: 26 Oct 2015 07:34 PM PDT Introduction Purpose The purpose of this report is to establish if a geothermal field can provide a medium for cooling chiller condenser water either in lieu of, or as a supplementary source to, the existing and future cooling towers. Alternate methods of cooling and heating provided by a geothermal field will save energy and dramatically reduce water consumption. This study also seeks to establish if water circulated through a geothermal field can provide precooling / preheating for the large amounts of outside air supplied to the current and future labs.  This report evaluates the current thermal performance of the existing systems to determine the geothermal fields needed capacity to support both the current and future needs of the buildings infrastructure. The thermal systems analyzed include the cooling tower, chiller and boiler systems located in the central plant. Overview The current building systems consist of three chillers rated at 500 tons (2) and one chiller at 88 tons, for a total connected tonnage of 1088 tns. There is one cooling tower rated at 600 tons that is inadequately sized to support heat evaporation for the 1088 tns chiller capacity.  The under sized cooling tower prevents the chillers from providing their maximum cooling capacity and degrades their operating efficiency, increasing energy consumption. Current water consumption can exceed the 25,000 gal/day limit imposed by the water authority. Future additional building will require approximately 300 tons of additional cooling and additional 780,000 gal/yr of water for evaporation via cooling towers. Additional water is also required for chemical treatment and regular blow down of total dissolved solids. Executive Summary Geothermal Field This study evaluates the likely location and capacity of a geothermal field to provide additional cooling and heating capacity, and reduce water consumption due to cooling tower water evaporation. A topographical site plan provided by CSW was used to locate areas suitable for drilling geothermal bores. The total numbers of bores are based on the availability of suitable (essentially flat) areas for drilling. Test bore data is not currently available and will be required prior to the completion of the construction document phase. Three test bores of approximately 400 feet will be required. When complete a flow test will be required to establish temperatures and thermal conductivity in three strategic locations within the geothermal field's perimeter. The test data will be run for no less than 36 hours and will be sent to a listed lab for analysis. The lab report will provide data on temperature and bore thermal conductivities for each location. This data will then be used in a computer-modeling program to establish the number, location & depth of bores required to match the heating & cooling requirements of the project construction documents. For the purposes of this study, we have assumed a bore yield of 178 ft/ ton, which is a conservative estimate, based on the data currently available for similar projects in Kentfield and Indian valley. Precise data will be provided from the test bores drilled on site prior to the completion of the CD phase documents. Based on our site survey and the topographical site plan we have established a maximum number of 516 bores can be installed on the site (See attached drawing) at 400 ft, this would provide a cooling capacity of 1126 tns EXISTING CHILLER PLANT CAPACITY AND EFFICIENCY The existing chiller plant consists of three chillers as follows 500 tns (2) 88 tns (1), for a total chiller tonnage of 1088 tns. The existing cooling tower however is derated due to compromised airflow, and is also undersized by approximately 488 tns. The net result is that the connected chillers cannot reach their rated capacity and have reduced efficiency. It is estimated that the current system is operating at approximately 1.45 KW/TN. Providing the existing machines with geothermal water at approximately 61 deg will increase the chiller efficiency by almost 100 % to around 0.76 KW/TN. Combined water savings due to no evaporation through the cooling tower will be around 5,837,168 gal/yr. GEOTHERMAL FIELD COOLING Option #1 provides 100% (875 tns) of cooling capacity for the total connected chiller loads for both new & existing buildings would have a pay back of 8 years and reduce energy consumption by $296,646 /year & reduce water consumption by 2,267,200 gal/yr.    The installation of a geothermal field would delete the need for the existing cooling tower and improve the existing chillers performance from around 1.45 KW/TN to 076 KW/TN. Note No new equipment is required for this option and the existing cooling tower is decommissioned. The annual energy cost reductions and life cycle cost analysis are as follows; Option #2 provides 57% (500 tns, or 1 chiller) of cooling capacity from the geothermal field. For the total connected chiller loads for both new & existing buildings, would have a pay back of 4.4 years and reduce energy consumption by $267,000 /year & reduce water consumption by 1,300,000 gal/yr. Note No new equipment is required for this option, and the existing cooling tower remains in service at reduced capacity. The annual energy cost reductions and life cycle cost analysis are as follows; LAB OUTSIDE AIR MAKE UP Currently the existing labs need around 151 tns of cooling for precooling of outside air. The new labs will require around 137 tns of cooling to treat outside air. This combined amount of 288 tns for pretreating lab outside air can be provided by the geothermal field. 61-degree water can provide air temperatures very close to and below room temperature even in summer design conditions. Geothermal cooling & heating energy is provided essentially free (less minor energy for water circulation). The total 288 cooling tons for treating outside air can be removed from the central plant chiller capacity, providing future central plant capacity for the future. No new chillers or cooling towers will therefore be needed for the new building, and 288 tns of central plant cooling capacity is added. The same magnitude of load reduction applies to the heating systems and their associated equipment. The annual energy cost reductions and life cycle cost analysis are as follows; Providing heating and cooling via the geothermal field will reduce water consumption resulting from cooling tower water treatment, blow down, and water evaporation by 748,000 gallons /year. In addition, water treatment chemical usage will be greatly reduced. Note; The existing lab AHU's coils will require modification for use with water from the geothermal field. Water consumption. All of the above options reduce water consumption dramatically. Option #1 combined with the geothermal outside air precooling / preheating option saves the most. Study Summary Option descriptions: A.    Geothermal – Provides precooling / preheating, to outside air for both new & existing buildings, saves approximately $243,719 per year in energy, has a pay back of 2 years, saves 748,800 gal/year of water and adds back 288 tons of chilled water and heating capacity to the central plant. B.     Geothermal – Option #1 provides 100% (875 tns) of cooling capacity for the total connected chiller loads for both new & existing buildings, would have a pay back of 8 years and reduce energy consumption by $296,646 /year & reduce water consumption by 2,267,200 gal/yr. C.    Geothermal – Option #2 provides 57% (500 tns) of cooling capacity for the total connected chiller loads for both new & existing buildings, would have a pay back of 4.4 years and reduce energy consumption by $267,000 /year & reduce water consumption by 1,300,000 gal/yr. The post A Geothermal Feasibility Guide appeared first on Poltrona.

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