Energy Systems Commons^™

Impact Of Evaporator Coil Air Flow In Residential Air Conditioning Systems, Florida Solar Energy Center, Danny Parker

FSEC Energy Research Center®

The performance of conventional split system residential air conditioners is highly dependent on adequate air flow across the evaporator coil. Sufficient air flow is necessary to achieve a proper balance between sensible and latent cooling capacity. Typical target air flow rates are approximately 350 - 450 cubic feet per minute per ton (581 - 747 L/S per kW) of cooling capacity. The authors have measured the air flow across the coil in 27 installations in Florida. Both flow hood and strip heat resistance methods were used to measure air flow with an established protocol. The installations measured ranged in capacity …

Solar Water Heating: A Question And Answer Primer, Florida Solar Energy Center, David L. Block

FSEC Energy Research Center®

Solar water heating is a technology that every homeowner can use to save dollars on utility bills. Questions most frequently addressed to the Florida Solar Energy Center (FSEC) about solar water heating are answered below. Please note that many replies are general and more explanation may be required for those with individual questions. For additional information, contact the FSEC

Solar Water Heating Options In Florida, Florida Solar Energy Center, John Harrison

FSEC Energy Research Center®

This document is intended to acquaint Florida's general public with typical methods of heating household water by means of the sun. The types of solar systems discussed are pumped (both direct and indirect), thermosiphon and integral collector storage.

Identifying Air Flow Failure Modes In Small Commercial Buildings: Tools And Methodologies For Building Commissioning Diagnostics, Florida Solar Energy Center, James Cummings

FSEC Energy Research Center®

A recent study of small commercial buildings in central Florida found that uncontrolled air flow -- including duct leakage, return air imbalance, and exhaust air/make-up air imbalance -- is widespread. Of 70 buildings studied, only 1 was identified as having no significant uncontrolled air flow. The causes of uncontrolled air flow include failure of design, poor workmanship, O&M problems, HVAC commissioning failures, materials degradation, and building retrofits. This study also found that the consequences of uncontrolled air flow are often quite severe and varied -- including high utility bills, occupant thermal discomfort, high humidity, mold and mildew growth, moisture damage …

Solar Hot Water Energy And Cost Savings For Typical Florida Residential Installations, Florida Solar Energy Center, David L. Block

FSEC Energy Research Center®

The following table presents energy and cost savings for four typical Florida solar water heating systems. Exact savings by a consumer may vary as much as plus or minus 25 from these numbers for numerous reasons. These include hot water usage, storage tank type, thermostat settings, solar system size, collector placement and local weather conditions. Computer simulations were used to generate the energy data.

Solar Heating Of Swimming Pools: A Question & Answer Primer, Florida Solar Energy Center, Charles Cromer

FSEC Energy Research Center®

Solar pool heating is one of the most economically attractive solar technologies in Florida today. If you are interested in heating your pool, or can no longer afford heating it with fossil fuel alone, consider installing a solar pool heater.

The following information helps answer the most frequently asked questions concerning solar pool heating in Florida. Keep in mind that much of this information is "rule of thumb"; your individual situation, if analyzed in detail, may differ somewhat from the general application. A more detailed analysis of pool systems is provided by the publications listed in the bibliography.

Evaluation Of Resources And Energy Systems At Fort Jefferson Garden Key, Dry Tortugas National Park, Florida Solar Energy Center, James Dunlop

FSEC Energy Research Center®

This report presents an evaluation of the resources and energy systems at Fort Jefferson, located on Garden Key in Dry Tortugas National Park, Florida. Conducted by Florida Solar Energy Center staff on June 11-12, 1997, this evaluation builds on a prior evaluation conducted in May 1989. The purpose of this evaluation was to document the energy and resource needs at the site, and to identify possibilities for reduced costs through conservation measures and renewable energy options.

Approximately 700 kWh of electrical energy is used at Fort Jefferson on a daily average, supplied exclusively by diesel-fueled generators. Average diesel fuel consumption …

Batteries And Charge Control In Stand-Alone Photovoltaic Systems: Fundamentals And Application, Florida Solar Energy Center, James Dunlop

FSEC Energy Research Center®

This report presents an overview of battery technology and charge control strategies commonly used in stand-alone photovoltaic (PV) systems. This work is a compilation of information from several sources, including PV system design manuals, research reports, data from component manufacturers, and lessons learned from hardware evaluations.

Field Measurement Of Uncontrolled Air Flow And Depressurization In Restaurants, Florida Solar Energy Center, James Cummings

FSEC Energy Research Center®

Field investigations were done in seven restaurants (subsample of a 63 commercial buildings study) to identify uncontrolled air flows and pressure imbalances. Testing included building airtightness tests, identification of building air barrier location, duct system airtightness, characterization of pressure differentials, building air flow balance, and infiltration/ventilation rates. All restaurants were found to operate at negative pressures which ranged from -0.003 inWC (-0.8 Pa) to -0.173 inWC (-43 Pa) and averaged -0.051 inWC (-12.7 Pa) under normal operation. The variables which affect depressurization are large exhaust fans, missing or undersized make-up air, intermittent outdoor air caused by the cycling of air …

History Of Applying Photovoltaics To Disaster Relief, Florida Solar Energy Center, William Young

FSEC Energy Research Center®

Hurricanes, floods, tornadoes, earthquakes, and other disasters can happen any place, any time. Major disasters destroy homes and businesses, and leave many people without adequate medical services, portable water, electrical service and communications. In response to the need for electrical service, solar energy offers a source of quite, safe, pollution-free power. Over the last few years, photovoltaic (solar electricity) power systems have provided energy for various disaster all over the country. Photovoltaics (PV) have been used to power vaccine refrigerators, medical equipment, lighting, radios, fans, communications, traffic devices and other electrical equipment. Previously, photovoltaics have supplied emergency power for Hurricane …

How Contractors Really Size Air Conditioning Systems, Florida Solar Energy Center, Robin Vieira

FSEC Energy Research Center®

This paper presents results from 489 of the 5559 Florida air conditioning contractors surveyed (an 8.5% response rate) regarding equipment sizing methods in new residences. Air conditioning sizing is accomplished by using ACCA's Manual-J procedure by 33% of the respondents, software by 34.4% of the respondents, square-footage by 24.2% and other estimate procedures by about 8.4%. Those using square-footage estimates varied from 350 square-feet- per-ton to 700 square-feet-per-ton. Over a third of respondents indicated oversizing intentionally on some jobs, in order to avoid complaints, accommodate future expansions, enable quicker cooling down of homes, and to allow for lower cooling set …

Are Energy Savings Due To Ceiling Fans Just Hot Air?, Florida Solar Energy Center, Patrick James

FSEC Energy Research Center®

Human comfort studies have shown that people prefer higher temperatures when they are subjected to a breeze. Ceiling fans are often used to create air motion in residences. Simulation studies (including one given in this paper) have demonstrated that in Florida, using ceiling fans combined with raising a home's temperature 2° F will generate about a 14% net savings in annual cooling energy use (subtracting out the ceiling fan energy and accounting for internally released heat). This savings drops to 2.6% with a 1° F increase in set point and to a negative 3.7% savings with only a 0.5° F …

Daylight Dimming Systems: Studies In Energy Savings And Efficiency, Florida Solar Energy Center, Lynn Schrum

FSEC Energy Research Center®

Three studies were conducted at Florida Solar Energy Center (FSEC) to study the lighting energy savings of daylight dimming systems. The Daylighting Test Facility (DTF) was used to study daylight dimming systems and how aperture orientation and blinds affect performance. The energy consumption was compared in two pairs of offices for all four window orientations: north, south, east and west. One office in each pair had blinds in a fixed position (down and open) and the other office had no blinds. The study showed that the energy savings ranged from 24% to 51% depending on the orientation and blinds.

The …

Measured Field Performance And Energy Savings Of Occupancy Sensors: Three Case Studies, Florida Solar Energy Center, David Floyd

FSEC Energy Research Center®

Occupancy sensors have the potential to significantly reduce energy use by switching off electrical loads when a normally occupied area is vacated. While occupancy sensors can be used to control a variety of load types, their most popular use has been to control lighting in commercial buildings. Manufacturers claim savings of 15% to 85%, although there is little published research to support the magnitude or timing of reductions. Energy savings and performance are directly related to the total wattage of the load being controlled, effectiveness of the previous control method, occupancy patterns within the space and proper sensor commissioning. In …

Demonstration Of Cooling Savings Of Light Colored Roof Surfacing In Florida Commercial Buildings: Our Savior's School, Florida Solar Energy Center, Danny Parker

FSEC Energy Research Center®

Architects and designers have long known that light-colored building roofs can reduce cooling needs. Recently, monitoring studies in Florida have made an effort to quantify these savings. Experiments in existing residences have shown that a white reflective roof can reduce cooling requirements by an average of 20%. However, until now there has been no investigation in Florida's climate to examine the potential in commercial scale buildings.

To remedy this need, a two year study was performed on a private elementary school building in Cocoa Beach, Florida. Our Savior's Elementary School was monitored for an entire year in a base line …

Results From A Comprehensive Residential Lighting Retrofit. 09-96, Florida Solar Energy Center, Danny Parker

FSEC Energy Research Center®

A single family residence in Miami, Florida was used as a case study to determine how residential lighting energy use could be reduced by substituting energy efficient lamps and fixtures. The three person household was chosen based both on its high utility bills and extensive use of interior lighting. A detailed audit revealed 40 lamps or bulbs on 26 controls (switches) with a total connected load of 2.5 kW.

All major energy using appliances in the home were sub-metered so that lighting and other plug loads could be differenced from the measured total power demand. Also, each of the individual …

Flastar: Florida Alliance For Saving Taxes And Energy Resources. Final Report., Florida Solar Energy Center, John Sherwin

FSEC Energy Research Center®

This document comprises the final project report in supporting the demonstration of the pilot Florida Public Building Loan Concept. This loan program provides low cost funds to eligible public entities for upgrade of building energy systems. The FLASTAR program (Florida Alliance for Saving Taxes And Resources) was modeled after the successful Texas LoanSTAR project [1, 2]. Within that program, funds provided from oil overcharges are loaned to various facilities for building system retrofits. These loans are repaid (with interest) from energy cost savings. As of the most recent reporting, the LoanSTAR program had saved the State of Texas some $13.7 …

Measured Impacts Of Air Conditioner Condenser Shading, Florida Solar Energy Center, Danny Parker

FSEC Energy Research Center®

A study has been conducted by the Florida Solar Energy Center (FSEC) to examine if space cooling energy savings can be achieved from shading of residential air conditioning (AC) condenser units. The investigation consisted of before-and-after experiments conducted on three homes over a two year period. A recent EPA study recommends shading of exterior AC condensers, using landscaping or other means, as a method to reduce space cooling energy use (Akbari et al., 1992).

Monitored Energy Use Patterns In Low-Income Housing In A Hot And Humid Climate, Florida Solar Energy Center, Danny Parker

FSEC Energy Research Center®

The Florida Solar Energy Center (FSEC) is metering energy use in two Habitat for Humanity developments. The objective is to understand how energy is used in low income housing and how it can be effectively reduced. The ten "control homes" come from a conventional housing project built by in 1993 Habitat for Humanity in Homestead, Florida. Another ten "experimental homes" have been recruited from the 190 home Jordan Commons development in the same vicinity. These houses, which are soon to be metered, are designed to be energy efficient with high SEER air conditioners, reflective roofing, solar water heaters and energy …

Side-By-Side Testing Of Commercial Office Lighting Systems: Two-Lamp Fluorescent Fixtures, Florida Solar Energy Center, Danny Parker

FSEC Energy Research Center®

Lighting systems in commercial office buildings are primary determinants of building energy use. In warmer climates, lighting energy use has important implications for building cooling loads as well as those directly associated with illumination tasks. To research the comparative performance of conventional and advanced office lighting systems, Florida Solar Energy Center (FSEC) set up the Lighting Flexible Test Facility (LFTF) which allows side-by-side comparison of lighting options in two otherwise identical 2.7 m x 3.7 m (9' x 12') south facing offices.

The ceiling of the LFTF contains 0.61 m x 1.2 m (2' x 4') recessed fluorescent fixtures designed …

Measured Performance Of Energy-Efficient Computer Systems, Florida Solar Energy Center, David Floyd

FSEC Energy Research Center®

The intent of this study is to explore the potential performance of both Energy Star computers/printers and add-on control devices individually, and their expected savings if collectively applied in a typical office building in a hot and humid climate. Recent surveys have shown that the use of personal computer systems in commercial office buildings is expanding rapidly. The energy consumption of such a growing end-use also has a significant impact on the total building power demand. In warmer climates, office equipment energy use has important implications for building cooling loads as well as those directly associated with computing tasks. Recently, …

Daylighting Dimming And Energy Savings: The Effects Of Window Orientation And Blinds, Florida Solar Energy Center, Lynn Schrum

FSEC Energy Research Center®

The Daylighting Test Facility (DTF) located at Florida Solar Energy Center, was used to study daylight dimming systems and how orientation and blinds effect energy savings. To evaluate the impact of blinds on dimming savings, the energy consumption was compared in two pairs of offices for all four window orientations: north, south, east and west. One office in each pair had blinds in a fixed position (down and open) and the other office had no blinds. From September through December of 1994, data were collected on the north- and south-facing offices. The DTF was rotated 90 degrees and data were …

Applying Photovoltaics To Disaster Relief, Florida Solar Energy Center, William Young

FSEC Energy Research Center®

Hurricanes, floods, tornadoes, earthquakes, and other disasters can happen at any time, often with little or no advance warning. They can be as destructive as Hurricane Andrew leaving several hundred-thousand people homeless or as minor as an afternoon thunderstorm knocking down local power lines to your home. Major disasters leave many people without adequate medical services, portable water, electrical service and communications. In response to a natural disaster, photovoltaic (solar electric) modules offer a source of quite, safe, pollution-free electrical power. Photovoltaic (PV) power systems are capable of providing the electrical needs for vaccine refrigerators, microscopes, medical equipment, lighting, radios, …

Uncontrolled Air Flow In Non-Residential Buildings, Florida Solar Energy Center, James Cummings

FSEC Energy Research Center®

The objective of this study was to develop the capability to substantially reduce energy use, building degradation and indoor air pollution caused by uncontrolled air flow in nonresidential buildings. For purposes of the study, 'uncontrolled air flow' was defined as air moving across the building envelope or between zones or components of a building, where the pathways of flow, the direction of flow, and the origin of the air are unknown, unspecified, or unintended. The study comes to three major conclusions as follows: 1. Uncontrolled air flow is pervasive in buildings, often resulting in severe -- and sometimes even catastrophic …

Energy Savings From Repair Of Uncontrolled Airflow In Eighteen Small Commercial Buildings, Florida Solar Energy Center, Charles Withers, Jr.

FSEC Energy Research Center®

Uncontrolled airflow, including duct leakage, pressure imbalances caused by closed interior doors, and exhaust/intake airflow imbalance, was characterized in 70 commercial buildings. In 18 of these buildings, uncontrolled airflows were repaired and energy savings from these repairs were monitored. In most buildings the retrofit was duct repair. In other cases, outdoor airflow was reduced and return air transfers were provided. Cooling energy use was reduced by an average 15.1% in these 18 buildings. With an average repair cost of $455 and average cooling energy savings of $195 per year, uncontrolled airflow retrofits proved to be very cost-effective. Various factors indicate …

Energy Efficient Office Building Design For A Hot And Humid Climate: Florida's New Energy Center, Florida Solar Energy Center, Philip W. Fairey

FSEC Energy Research Center®

Hot and humid climates, such as those in Florida, pose unique challenges to architects and engineers seeking energy efficient office building designs. The severe impact of internal loads on cooling, the intense solar conditions and the need for increased ventilation set against high relative humidities, all serve to limit the success of many conventional methods of reducing building energy use. To provide a high-visibility demonstration of potential energy design solutions, the Florida Solar Energy Center (FSEC) is building a state-of-the-art office complex for its new facility in Cocoa, Florida.

The Measured Summer Performance Of Tile Roof Systems And Attic Ventilation Strategies In Hot, Humid Climates, Florida Solar Energy Center, David Beal

FSEC Energy Research Center®

During 1994, simultaneous full-scale testing of residential plywood-decked roofing system was conducted using a flexible roof facility (FRF). The facility consists of a 24-ft by 48ft rectangular building with one large conditioned space under an attic that is partitioned into six separate test cells. Throughout the test protocol one cell was configured as a residential black-shingle roof system, employed as the baseline for comparison of the alternative roofing systems.

Two identical cells were employed during the summer of 1994 to investigate soffit and ridge venting. Tests of two different configurations best illustrate the results. A comparison of a sealed attic …

Measured Cooling Energy Savings From Reflective Roofing Systems In Florida: Field And Laboratory Research Results, Florida Solar Energy Center, Danny Parker

FSEC Energy Research Center®

A series of field experiments in Florida have examined the impact of reflective roof coatings on air conditioning energy use in occupied homes. The tests were conducted on nine residential buildings from 1991 to 1994 using a before and after protocol where the roofs were whitened at mid-summer. Measured AC electrical savings in the buildings during similar pre- and post-retrofit periods averaged 19%, ranging from a low of 2% to a high of 43%. Utility peak coincident peak savings averaged 22%. Cooling energy reductions appear to depend on ceiling insulation level and roof solar reflectance, air duct system location and …

Florida Exterior Wall Insulation Field Test: Final Report, Florida Solar Energy Center, Stephen Barkaszi

FSEC Energy Research Center®

The Florida Solar Energy Center (FSEC) and Oak Ridge National Laboratory (ORNL) have conducted a field test of exterior insulation applied to Florida masonry residences. Approximately 50% of Florida's six million existing residences are of concrete block construction. Many of these homes, particularly those 15 years or older, have uninsulated walls.

Within the project, two single-family homes in Central Florida were extensively monitored to measure the energy savings of the technology. The primary objective was to examine the effect exterior insulation has on air conditioning (AC) energy use and peak electrical demand for two typical residences. A secondary objective was …

Smarts2, A Simple Model Of The Atmospheric Radiative Transfer Of Sunshine, Florida Solar Energy Center, Christian Gueymard

FSEC Energy Research Center®

An upgraded spectral radiation model called SMARTS2 is introduced. The solar shortwave direct beam irradiance is calculated from spectral transmittance functions for the main extinction processes in the cloudless atmosphere: Rayleigh scattering, aerosol extinction, and absorption by ozone, uniformly mixed gases, water vapor, and nitrogen dioxide. Temperature-dependent or pressure-dependent extinction coefficients have been developed for all these absorbing gases, based on recent spectroscopic data obtained either directly from the experimental literature or, in a preprocessed form, from MODTRAN2, a state-of-the-art rigorous code. The NO2 extinction effect, in both the UV and visible, is introduced for the first time in a …