Habitat for Humanity is building nearly 150 new homes forlow-income victims of Hurricane Andrew. The goal of theproject is an energy-efficient neighborhood to stand as a benchmarkof affordable housing in Florida.
Jordan Commons in southern Dade County is an innovative,energy-efficient housing development being constructed forlow-income victims of Hurricane Andrew. The goal of theproject is to build an energy efficient neighborhood to serve as amodel for affordable housing in Florida. Habit at forHumanity is developing the 40-acre tract and will oversee theconstruction of nearly 150homes.
The homes, which vary in size from 950 to 1,450 square feet,feature a number of energy-efficiency measures recommended by theFlorida Solar Energy Center (FSEC):
•Energy efficient envelope design
•Shaded- or low-transmittance windows
•Reflective white roof and light-colored walls
•Duct system within the conditioned space
•Landscape shading
•Small,high-efficiency air conditioners
•Solar water heaters
•Low-flow showerheads
•Efficient refrigerators
•Compact fluorescent lighting
Perhaps most importantly, the households that incorporate theefficiency features are being monitored for one year to documenttheir energy savings — a proof-of-concept seldom attempted. With support of the Florida Energy Office, FSEC is monitoring 10homes in the energy-efficient development and comparing them with10 control homes without energy-efficient features in nearbyFlorida City. The parameters listed in the chart on back willbe monitored in both neighborhoods.
FSEC assistant John Broughton installs sensors on the roof ofone of the monitored homes .
Temperature measurements are obtained using type-Tthermocouples. The ambient air sensor was shielded fromdirect radiation by placing it inside a vented enclosure. Capacitive-type humidity transmitters provide temperaturecompensated RH readings. Cupped wind speed anemometers aremounted one meter above the roof line. Insolation is measuredusing a horizontally mounted silicon-cell pyranometer located onthe roof top. Window ventilation is obtained from magneticcontact switches mounted on the operable windows that send signalsback to the datalogger. Electrical power consumption wasassessed using eight 50-and 200-amp, pulse-initiating powertransducers.
CR10 dataloggers read instrument data at 5-secondintervals. Integrated or totalized values are stored every 15minutes. Data are transferred from the data-loggers to amainframe computer each evening and automatically plotted tosummarize the daily performance parameters measured at eachsite. The project engineer reviews the plots the followingmorning to ensure reliable data collection.
FSEC research engineers audited the10 control group sites withdataloggersand associated instrumentation installed inJuly of 1994.To our knowledge,thiseffort represents the most ambitiouscol-lection of energy end-use data in low-income housing in NorthAmerica.
Before we installed the instrumenta-tion,many predicted thatenergy for heat-ing water would be greater than any otherenergy usein the homes. Hot water use isstrongly linked tooccupancy,and the con-trol houses average more than four per-sonsper household. However,the datashowed that nearly half theenergy usedwas for air conditioning. The nextlargestuse,water heating,was much lower at 18percent. So muchfor pre-monitoringspeculation.
As we further examined the air condi-tioning data,an intriguingfact surfaced:among the 10 control homes,which arenearlyidentical,the AC use varied by 5:1.Again,however,the detailed dataallowedclear insight into the differences. Wefound that thethermostat setting ex-plained more than 80 percent of thedif-ference in AC energy use from one hometo the next. Foreach degree the thermo-stat was set below 81°F,the AC useincreasedby 12 percent.
Based on such data,we have been ableto make better informeddecisions to im-prove construction of the efficient homes.But thereal test is just beginning. WithJordan Commons now underconstruction,FSEC will be installing the monitoringequipment forthe 10 experimental homes.At the end of one year ofcomparativemonitoring,the accumulated data taken atJordan Commonswill be analyzed againstthat taken from the control group homesinFlorida City. The results should allowthe verification ofperformance of theenergy-efficiency measures and serve asthe basisfor improving affordable hous-ing in Florida into the next century.