San José, Costa Rica, since 1956

How Green Was My Energy-Efficient House?

When Andrea Meoño fills up a glass of water to stave off the afternoon heat, it is rainwater – collected from her roof, filtered and treated – that she guzzles.

When she switches on the TV, the afternoon telenovelas flickering across the screen are powered by solar panels and a wind turbine.

The kitchen stove uses biogas captured from rotting compost. Her toilet flushes with recycled drain water.

Meoño spends her days in La Casa Autosuficiente (The Self-Sufficient House), the latest permanent exhibit at the environmental theme park INBioparque, just north of San José in Santo Domingo de Heredia.

The Casa Autosuficiente is a showcase of simple (some less-so) features that drastically reduce the environmental impact of daily living, and are intended to spark awareness about environmentally friendly alternatives and options available in Costa Rica.

“The idea is to show Costa Ricans that there are things you can do in your own home,” said Meoño, an employee of the National Power and Light Company (CNFL).

While Meoño doesn’t live at the house, every morning she drives a small electric truck from her CNFL office to INBioparque, stores her lunch in the energy-efficient refrigerator and waits for visitors.

Opened in January, the Casa is the fruit of work by the National Biodiversity Institute (INBio), CNFL, and a handful of businesses selling environmental products and technologies.

“The idea is to represent your common house in Costa Rica,” said Leydi Hernández, a guide with INBio who also ushers visitors through the Casa Autosuficiente.

Inside the small, 1.5-bedroom house, the kitchen sports an Oster rice cooker, a Black & Decker blender and coffee maker, and a General Electric refrigerator, all certified energy efficient by Energy Star, a certification program developed by the U.S. Environmental Protection Agency and the U.S. Department of Energy.

“We often try to get our appliances to match, all white or all black,” said Meoño, noting that this was not the case in the Casa Autosuficiente. “This aesthetic sometimes makes us pay. It’s better to look for efficiency.”

The house also saves energy on lighting. The living room is lit by a single fluorescent tube set in an aluminum fixture that has two reflective sides, which amplify and spread the tube’s light.

In the bathroom, the energy efficient compact fluorescent bulb runs on a switch that automatically turns the light on when the bathroom door opens, and shuts it off when the door closes. In the hallway, Costa Rican-based Solatube installed a natural light fixture that uses a glass dome on the roof of the house to capture sunlight, which is then reflected down through a tube and diffused from a small glass pane too bright to look directly into.

The Casa Autosuficiente is also equipped with a standard solar hot water heater placed on the roof of the house, where water is piped through black metal tubes under double-pane glass that heats it without the use of electricity. A quick test of the water-saving shower in the bathroom shows there is little wait before near-scalding water is available.

According to Meoño, the Casa Autosuficiente uses less energy than what is produced by the solar arrays and wind turbine, but she acknowledges that she does not give it the use that a family that lived there full time would.

That excess electricity is measured by an intelligent bi-directional meter and sent back through the transmission lines into the national electric grid. A bill currently in the Legislative Assembly would allow customers to receive money from CNFL or the Costa Rican Electricity Institute (ICE) for every excess watt they produce and send to the grid.

Inside the house, a digital readout next to the electric meter can cycle through exactly how much energy is being produced by each source, and how much is being used, and a variety of other details. These details can also be brought up on a computer and even accessed on the Internet.

Two companies, Agua Solutions and ASI Power & Telemetry, supplied the bulk of the water and electricity infrastructure used at the Casa Autosuficiente. Both companies are managed by Jim Ryan, who came to Costa Rica in 2001 from the U.S.

In front of the house, is a 1.2-kilowatt wind turbine called a Windspire, which uses blades that run vertically to catch the wind coming from any angle, and spin tight circles around a central post.

“This is the first one to be installed in Central America,” Ryan said. “It’s a nifty unit because it’s quiet. You can stand five feet away from it, and it will be a whisper. And it can accept wind from any direction, so it doesn’t have to search for wind or spin around.”

Behind the house, two arrays tilt a total of eight solar panels toward the south at an angle of between 10 and 11 degrees to maximize their exposure to the sun. According to Ryan, each panel can produce up to 135 watts, and together have a capacity of just over 1 kilowatt.

Both power-producing stations run the electricity to the house and to eight absorbent glass mat (AGM) batteries, which, Ryan said, are safer and more efficient than a standard car battery.

The water system built by Ryan’s Agua Solutions, meanwhile, aims to conserve and reuse nearly all the water used in the house, and captures a much of it from the sky.

When a storm cloud opens up above the Casa Autosuficiente, as they are known to do, large gutters along the edges of the roof catch the rain and funnel it through a pair of stainless steel filters to a 5,000-liter storage tank. From there, it is pumped through a water pressure tank and standard water filter before entering a GE Homespring Central Water Purifier.

“It is designed to give you absolutely safe drinking water anywhere in the house,” Ryan said. “The unique thing about this system is that it absolutely removes all pathogens so you have pure water and does it without electricity. Because it is supplied by a pressurized system, even if the electricity goes out, if there’s water pressure, you have pure water.”

In addition, the house reuses water from the shower and sinks to supply the dual-flush toilet, which releases two different levels of water depending on what is being flushed.

For information on the electric or water systems, contact either Agua Solutions or ASI Power & Telemetry see their Web sites and www.

For more information about the Casa Autosuficiente, contact INBioparque at 2507-8107.


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