This article was originally published in the May/June 1996 issue of Home Energy Magazine. Some formatting inconsistencies may be evident in older archive content.


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Home Energy Magazine Online May/June 1996


The Lumens Are Growing. As of last October, the lumen grew 1.1%-according to the National Institute of Standards and Technology (NIST). The NIST established a new luminous scale with a slightly larger value than the previous standard. For example, a light source that was rated at 100 lumens per watt (Lm/W) will now have a new rating of 99 Lm/W, a difference that is barely noticeable to the human eye. This new luminous flux scale will help standardize the values with other national standards laboratories around the world, such as the German PTB. Lighting Futures 1, no. 2. Lighting Research Center, Rensselaer Polytechnic Institute, Troy, NY 12180-3590. Tel:(518)276-8716; Fax:(518)276-2999.

EEMs Expand Nationwide. The U.S. Department of Housing and Urban Development expanded the Federal Housing Administration's (FHA) Energy-Efficient Mortgage (EEM) pilot to all 50 states last October. The FHA loan program offers incentives for homeowners to purchase energy upgrades, and it permits buyers to finance 100% of eligible energy retrofits without requiring a new appraisal or additional credit qualification. Energy savings are determined by a home energy rating or an energy auditor. The loan limit for existing or newly constructed one- and two-family homes must be 5% of the property's value, not to exceed $8,000; maximum loan amounts may exceed statutory limits depending upon the cost of eligible improvements. Adjustable rate mortgages and 203(k) rehabilitation loans are also eligible. Alliance Update, Fall 1995. Alliance to Save Energy, 1725 K St. NW, Suite 509, Washington, DC 20006-1401. Tel:(202) 857-0666; Fax:(202)331-9588.

Linear Power Supply Gains High Efficiency. A new technology for solar homes offers more power for the dollar. Zane International Incorporated is manufacturing a high-efficiency adjustable linear power supply that is compact, relatively inexpensive, and ideal for solar electric homes and recreational vehicles. Depending on the output voltage, Zane's linear power supply has efficiencies as high as 88%, unlike most others, which have efficiencies of about 50%. A standard linear supply (1 or 2 amps) is approximately the size of a cigar box and sells for $40-$100 retail. Zane's 2-amp unit fits in a standard, single-width wall box and costs about $50 retail; the 8-amp version, enclosed in its own palm size circuit box, costs $110-$115 retail. Zane suggests that the units can power cellular phones, answering machines, laptop computers, and other low-voltage DC equipment directly from a DC battery bank without interference. Both units are available in 12- and 24-volt (V) versions, and the output voltage is user adjustable from 2 V below the input voltage all the way down to 1.2 V. In solar electric homes, the units hold precise voltage with no spikes, and their efficiencies are comparable to those of an inverter. Their no-load DC current draw of about 14 milliamps (mA) is an advantage over typical Trace inverters. Demand-Side Technology Report, Dec 1995. Cutter Information Corp., 37 Broadway, Suite 1, Arlington, MA 02174-5552. Tel:(800)964-5118; Fax:(617)648-1950.

Salts in the Attic Insulate. Researchers at Oak Ridge National Laboratory have been testing a new attic insulation material that reduces and delays summer cooling load by absorbing heat from the attic during the day and releasing it again at night. Salt is the magic ingredient in this new material (developed by Phase Change Technologies, West Lake, Ohio). The salt (calcium chloride hexahydrate) is embedded into perlite insulation, packed into plastic containers, and installed in the attic between layers of conventional insulation. The salt stores thermal energy as it melts to a liquid at around 80oF, and releases it when it cools to a solid. During the day, the material absorbs and intercepts heat from the attic before it can penetrate the ceiling and enter the home. At night, when the temperature drops below the solidifying point of the salts, the heat is released back to the attic without ever adding to the house cooling load. The phase change from liquid to solid also delays the peak heat gain into the house by several hours, thus shifting the peak load to the late afternoon. Test results show that the phase change material can reduce total house cooling load by 19%, compared to a house with conventional R-19 attic insulation. However, researchers agree that additional testing is required before commercialization. Energy Design Update, Nov 1995. 235 W 102nd St. No. 7J, New York, NY 10025. Tel:(212)662-7428; Fax:(212)662-0039.

Blower Door Controller Gets Automated. The Minneapolis Blower Door, manufactured by the Energy Conservatory, has been automated. A custom-made data logger reads pressure from the blower door and sends back signals to control blower speed. The data logger is controlled by an ordinary laptop computer and can even be run by the smaller palmtop computers. In addition to single-point airtightness tests, the system is also capable of running tests according to American Society for Testing and Materials (ASTM) or Canadian General Standards Board (CGSB) procedures that specify measurements at six or seven different pressure points.

Setting up the fully automated controller is easy. Two plastic tubes and one cable with modular phone jacks connect the data logger to the blower door. A second cable connects the data logger to the serial port of the computer.

The data logger and software can also be used to measure leakage with the Minneapolis Duct Blaster. The Energy Conservatory plans to sell temperature, humidity, pressure, and carbon monoxide sensors that are compatible with the data logger.

The price for the data logger, software, and retrofit to an existing Minneapolis Blower Door is $1,500. The user supplies her or his own computer. A new Minneapolis Blower Door with the automated controller costs around $3,000. Energy Design Update, Jan 1996. 235 W 102nd St. No. 7J, New York, NY 10025. Tel:(212)662-7428; Fax:(212)662-0039.


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