B09_140G0221R0018-1_Attch_8_Energy_Assessment_0001.docx

HMO / NWS-PTWC Ewa Beach, HI Energy Summary

Executive Summary

The site contains approximately 16,300 square feet of building space consisting of residences, offices, and electronic monitoring spaces. These buildings have various occupancy patterns and energy usage depending on the application of the space. Electricity is metered at the site level but not at each individual building.

KS also recommends the use of several low-capital modifications that create relatively small energy savings but have short payback periods. High-capital modifications that create large energy and cost savings, such as installing new power generation systems and alternative HVAC technologies, should be investigated further to determine payback period and feasibility.

HVAC System Overview

The Operations Room is served by (3) 3 ton ductless split ceiling cassettes and (1) ¾ ton wall mounted unit with the condensing units located at grade. Temperature control is local. There is no heating system.

UPS 2 room is also cooled 24/7 and is served by a 3 ton Frigidaire thru-wall unit.

The Garage is served by a 3 ton ductless split AC unit.

The Electronics Shop is served by a 2 ton Carrier ductless split AC unit.

The Office is served by a Panasonic 5,000 Btuh thru-wall unit.

The condensing units for the split systems are located outside on grade. There is no heating system. Due to the distributed nature of the HVAC systems, there is no central building automation system. Temperature control is local, and no monitoring is performed.

Magnetic Absolutes Building #10, Magnetic Variation Building #11

There are no heating or cooling systems serving these buildings.

Special Areas

Domestic Cold and Hot Water

The Operations Building has a 4-gallon, 1.5 kW tank type under-counter electric water heater.

The Electronics Shop Building No. 6 only has cold water. The other buildings do not have plumbing.

Assessment of energy cost and efficiency through an analysis of energy bills;

On-site survey of existing conditions;

Identification of low-cost or no-cost energy conservations measures;

List potential capital improvements that merit further investigation.

This publication recommends a preliminary energy-use analysis (PEA) to determine a building’s current energy use relative to similar buildings. This analysis uses the following methodology:

Determine basic building characteristics: gross building area, use and occupancy patterns.

Assemble and summarize utility bills for at least a one-year period. Review the bills for opportunities to lower costs by taking advantage of different utility rates. Review bills for irregularities.

Develop the energy use intensity (EUI) and energy cost intensity (ECI). Energy use intensity (EUI) is the annual total energy consumption divided by the gross building area, with units of Btu/ft2-year. Energy cost intensity (ECI) is the annual total energy cost divided by the gross building area, with units of $/ft2-year.

Compare the EUI and ECI to buildings with similar chacateristics.

After the PEA is completed, the energy assessment consists of the following steps:

Walk-through survey of the building;

Meet with the building owner and tenants to understand operations issues and areas of concern;

Perform a space function analysis to determine if efficiency is affected by functions different than the original intent;

Identify no-cost or low-cost changes to the facility or operations and maintenance (O+M) procedures and estimate approximate savings;

Identify potential capital improvements for further study.

Utility Consumption Analysis

FY 2009: 99,023 Btu/ft2-year FY 2010: 107,955 Btu/ft2-year FY 2011: 103,674 Btu/ft2-year

Because of the unique nature of this site, benchmarking is difficult. The US Energy Information Agency has developed a database (the Residential Building Energy Consumption Survey) of EUI’s for many residences, but it does not break out Hawaiian residences separately and does not include mixed-use sites.

FY 2009: 5.45 $/ft2-year FY 2010: 6.35 $/ft2-year FY 2011: 7.44 $/ft2-year

Because of the unique nature of this site, benchmarking is difficult. The US Energy Information Agency has developed a database (the Residential Building Energy Consumption Survey) of ECI’s for many residences, but it does not break out Hawaiian residences separately and does not include mixed-use sites.

The site is centrally metered: individual building consumption data is unavailable.

Thirty-nine months (October 2008 through December 2011) of electricity demand and consumption billing information was analyzed. Although the demand component of the electricity rate ($/kW) is about the same as in the mainland, the site demand (kW) is low, resulting in the demand charge being only 7% of the total cost of electricity.

Electricity consumption information was derived from billing information and this raw information is presented in Appendix 1. The monthly electricity consumption was plotted against month on a radar-type chart and is shown below. The radar plot showed consumption was relatively flat – the maximum-to-minimum consumption ratio was 1.61, suggesting that cooling loads do not influence electricity consumption much. For climates having defined summer and winter seasons, the ratio is often over 2.

To test this hypothesis, the electricity consumption was correlated to cooling degree days. Cooling degree days are a single-measure, simplified means of characterizing outside air temperature data. Cooling degree days are a measure of how much (in degrees F) and for how long (in days), outside air temperature was higher than a base temperature (65°F).

Actual cooling degree day information was obtained for the same timeframe as the electricity consumption data. The cooling degree day information is traceable to the National Climatic Data Center for the Honolulu Airport weather station.

The correlation coefficient measures the linear relationship between two variables: the correlation coefficient ranges between 1 and -1. A value of 1 means that if one variable increases, the other variable increases linearly. A value of -1 means that if one variable increases, the other variable decreases linearly. A value of 0 means there is no linear correlation between the two variables.

Electricity consumption and cooling degree days have a correlation coefficient of 0.62, which means that the two variables are only weakly related. A scatter diagram of the two variables, shown below, confirms the weak relationship.

Comparison of two parameters suggests if equipment or lighting operates when the building is unoccupied. The two parameters are:

The electricity load factor (ELF), defined as the ratio between the average daily use and the maximum possible use if the peak demand operated for a 24 hour period, and

The occupancy factor (OF), defined as the percentage of time that the building is occupied.

If the ELF is much greater than the OF, that implies that equipment or lighting operates when the building is unoccupied.

The electricity load factor (ELF) was calculated as 0.73 for June 2012. The occupancy factor cannot be precisely calculated, because the central power meter serves several types of buildings. But approximately 60% of the building area is housing, which has an occupancy factor of 60%. The ELF is not much greater than the OF, which suggests that lighting and equipment left on during unoccupied times is not a significant energy drain.

The conclusions of this billing-information analysis are:

Air-conditioning does not drive electricity consumption, so baseload consumption (receptacles and lighting) represents a target for energy-conservation measures. Air-conditioning use is also significant and remains another energy-conservation target.

Operation of HVAC equipment, lights and receptacles during unoccupied hours is not significant, but still represents an energy-reduction target.

The site is centrally metered. Individual building consumption data are unavailable.

Thirty-nine months (October 2008 through December 2011) of water consumption billing information was analyzed. Average monthly water consumption was plotted against month on a radar-type chart and is shown below. The radar plot shows that consumption peaks do not coincide with summer months, but reach their minimum in the winter. The August 2011 water consumption is much higher than others, and resembles an outlier that was disregarded in this analysis.

The connection between cooling and water usage was tested by correlating cooling degree days against water consumption. Water consumption data were plotted against the cooling degree days for each month on a scatter diagram, as shown below.

Water consumption and cooling degree days have a correlation coefficient of 0.50, which means that the two variables are only weakly related, as shown in the scatter diagram.

The conclusion of this billing-information analysis is that baseload consumption (toilets and lavatories) and lawn irrigation represent the best targets for reduction measures.

The United States Green Building Council (USGBC) established the Leadership in Energy and Environmental Development (LEED) rating system as a way of measuring previously-undefined green buildings. While this has been widely applied to new construction and renovation projects, the LEED for Existing Buildings: Operations and Maintenance (LEED EB O+M) rating system measures the sustainability of existing buildings.

The rating system encourages sustainable practices in existing buildings, especially targeting these areas:

Exterior building and site maintenance;

Energy and water use reduction;

Environmentally-preferred cleaning products;

Waste management;

Indoor environmental quality.

Buildings must apply for recertification at least once every five years to maintain their status. The latest version of the rating system was issued in 2009 and will likely be revised in November 2012.

The rating system consists of a checklist of sustainable items in eight categories. Points are achieved for each completed sustainable item. “LEED Certification” requires 40 points; advanced levels are possible with higher point counts: Silver (50), Gold (60) and Platinum (80).

The project would register with USGBC, complete the checklist and electronically submit backup evidence. An independent agency reviews the checklist and supporting documents and determines the final point count, which in turn defines the level of certification.

Energy and Atmosphere Prerequisite 2 (minimum energy efficiency performance) requires that the building receive an Energy Star rating of 69. This rating means the building is in the 69th percentile (i.e., it consumes less energy than 69% of similar buildings). Based on the discussion above, it is difficult to benchmark this site against other facilities.

Another potential energy goal is to be “carbon-neutral”, or to reduce a building’s carbon footprint. “Carbon footprint” is defined as a building’s carbon dioxide emission rate in metric tons. Carbon dioxide is linked to global warming effects.

Since a majority of Hawaiian electricity is generated by burning oil (which emits carbon dioxide), achievement of this goal would be met by using photovoltaic arrays to generate electricity, or buying renewable energy credits.

Another target would be to make the site a net-zero energy site.

For a net zero energy site, the annual energy generated by onsite renewable energy equals the energy consumption of the building. The building is still connected to utilities, and uses those utilities at peak times, but contributes power back to the utility at other times. The amount exported to the utility equals the amount purchased from the utility; the exports and purchases occur at different times.

Satisfying the net zero energy requirement would be achieved by purchasing renewable energy credits or using photovoltaic arrays to generate power.

Energy Star residential appliances;

Residential central air conditioning maintenance;

Residential solar water heating equipment installation;

Residential household energy monitoring;

High efficiency packaged and split AC systems;

Variable speed drives on HVAC equipment;

Lighting upgrades.

Power Generation Technologies

In the gas turbine cycle, an air/natural gas mixture undergoes a combustion process to form high-temperature flue gases, which rotate a gas turbine to generate electricity. The flue gases exiting the gas turbine are still approximately 450°F and are routed to a heat exchanger, which creates hot water to be used by the facility.

Gas turbines are available in small capacities (“microturbines”) as low as 30 kW. At that capacity, the available heat recovery is 200,000 Btu/hr. This power generation system would run most often in the summer to reduce peak power demand. However, there is no appreciable hot water user that would allow this heat to be recovered. Without flue gas heat recovery, the cogeneration system is not economical since the power generation efficiency is low without heat recovery.

Therefore, cogeneration is not recommended.

Although PV economics are limited by high capital cost on the mainland, the high cost of electricity in Hawaii means that PV payback periods there will be reduced, and these systems should be further assessed.

Wind Turbine Power Generation

Wind energy can be used to generate power by rotating wind turbines.

Although wind-turbine economics are limited by high capital cost on the mainland, the high cost of electricity in Hawaii means that payback periods there will be reduced, and these systems should be further assessed.

Fuel cells are commercially available but are still at a high pricing point because an economy of scale has not been reached. Because of the unfavorable economics, this technology is not recommended.

Alternate HVAC Technologies

Applying this technology to the Operations Building should be investigated.

The leaked air is not used beneficially, but has used cooling and fan energy.

The Sheet Metal and Air-Conditioning Contractors’ National Association (SMACNA) publishes the “HVAC Air Duct Leakage Test Manual” to assist contractors and members in specifying duct leakage rates and conducting duct leak tests. Duct leakage is often specified by percentage of leakage: the duct system is allowed to leak up to 3% of the design airflow.

The leakage rate can be reduced by sealing seams and joints. This leakage reduction is most easily achievable for supply and return ducts in accessible locations. The expected simple payback for sealing the ductwork is about 6 years and should be pursued.

Low-resistance filtration is not commercially available for residential applications, but should be pursued for the central system in the Operations Building. Although a large savings is not expected, the investment is not very large, since filter replacement labor cost is the same as replacement with higher-resistance filters.

Incandescent lighting should not be replaced with higher efficiency light sources in the Magnetic Absolutes and Magnetic Variation Buildings as this would interfere with the scientific equipment.

Occupancy sensors should not be installed in the broadband seismometer room in the Seismic Vault building since the lights must remain on 24/7 to provide heat to the equipment.

No night time setback should be applied to spaces which require 24/7 cooling (UPS 1 and 2 rooms).

A display screen located at a common point (where it can be viewed by all occupants) creates energy savings by reminding occupants of the issue and modifying their behavior. The screen would display:

Real-time and historic electricity consumption;

Energy consumption comparisons between internal users (departments);

Weather forecasts;

Tips for conservation;

Sustainable features implemented into the building.

The display screen is often termed an “energy dashboard” because it captures and graphically summarizes the energy performance of the building in the same sense that a dashboard shows operating parameters of a car.

The installation cost of an energy dashboard is sensitive to the degree of customization and the extent of information capture and would only apply if the submetering discussed above is implemented.

Power System Improvements to Reduce Energy Use

In a commercial building, the highest phantom power users are computer workstations and monitors. Phantom power can be reduced by setting computers to power-saving (hibernate) mode when not in use.

Power strips are available which de-energize six outlets on a timed basis (for printers, lamps, monitors and chargers), but keep two outlets powered at all times (for computers, clocks, phones, etc.).

Although computer manufacturers have reduced phantom power losses over the last five years, the latest edition of the energy standard (ASHRAE Standard 90.1-2010, for new construction) requires that 50% of electrical outlets in offices and classrooms be switched off at night.

The energy-conserving power strips cost $30. Savings are expected to be about $3 per workstation and should therefore be pursued, at least as new equipment is purchased.

Water Use Reduction

Most of the existing toilets use 1.6 gallons per flush. Low-flow flushometer valves can be retrofitted that reduce consumption to 1.3 gallons per flush.

A low-flow 1.3 gpf valve is not recommended for retrofit to the 3.5 gpf toilet in the women’s room of the Operations Building. Instead a 1.6 gpf valve should be retrofitted, or the toilet should be replaced entirely with a lower-flow fixture.

Automatic sprinkler valving, which shuts the irrigation system off automatically when it is raining;

Pressure regulating devices, which reduce pressure available at the nozzle, in turn reducing the water flow;

Direct-to-plant root watering systems, which drip water into the root system, which conserves water relative to watering the surface and allowing water to seep through to the root system;

Microprocessor control of the irrigation system, which would optimize water flow and timing, considering site slope, plant species and climate data in order to minimize water evaporation;

High-efficiency nozzles, for more uniformly distributed water.

The sealant around several windows in Employee Housing #1 and 5 is deteriorating. Replacing this sealant is an inexpensive way to increase the energy efficiency of the windows.

The Electronics Shop has an exterior door that currently does not have weather stripping installed. This gap underneath the door allows further heat gain to the space, so it is recommended that weather stripping be installed.

The residential attics are insulated with 6” R-19 fiberglass blanket insulation at the floor. In a few instances this insulation has been moved out of place and needs to be put back to its proper location to be fully effective. Also, upgrading the insulation in the attics to a larger R-value will have a short payback period and should be pursued.

The rest of the buildings on site currently have un-insulated attics or roofs. Since some of these buildings are either cooled 24/7 due to electronic equipment inside or cooled during occupied business hours, these exterior elements should be insulated. It is not necessary to add insulation to the Magnetic Absolutes and Magnetic Variation buildings since they are not mechanically cooled or heated.

$34,675.84

$34,270.78

$31,069.85

May-12

Jun-12

Jul-12

Aug-12

Sep-12

$15,958.65

HMO / NWS - PTWC Ewa Beach, HI KS Project No. K3000600 Assessment Date: August 16, 2012 Final Submittal: January 25, 2013 5 Energy Summary - 1 Comprehensive Condition Assessment image4.png image5.jpeg image6.jpeg image1.png image2.gif image3.png image7.png