Zero+Energy+Buildings

-Andrew Shaw

Zero Energy Buildings

This article is a conference paper published by the National Renewable Energy Laboratory that investigates the multiple definition of a ‘zero energy’ building.66 A zero energy building is a residential or commercial building with low energy needs. These lowered energy needs are a result of efficient design plans and the utilization of available renewable energies. This paper looks at current low-energy buildings and explores the energy levels of a zero energy building.

Energy Efficient Buildings investigated - “Oberlin” – The Adam Joseph Lewis Center for Environmental Sutdies, Oberlin College. - “Zion”- The Visitor Center at Zion National Park, Springdale, Utah. - “Cambria”- The Cambria Department of Environmental Protection Office Building, Edsburg, Pennsylvania. - “CBF”- The Philip Merrill Environmental Center, Chesapeake Bay Foundation, Annapolis, Maryland. - “TTF” – The Thermal Test Facility, National Renewable Energy Laboratory, Golden, Colorado. - “BigHord”-The BigHorn Home Improvement Center, Silverthorne, Colorado. - “Science House” Science Museum of Minnesota, St. Paul, Minnesota.

Zero Energy Buildings, at its base definition, are buildings that meet their own energy needs through local renewable energy. Buildings can utilize on site renewable energie technologies or off-site utilities, on sight are preferred. Most buildings are still connected to the grid to ensure stabile electricity to, sometimes from, the building. A zero energy goal for a building is site specific, technologies that may work for one example will fail in another.


 * Definitions of Zero-Energy Buildings**

• __Net Zero Site Energy__**:** A site Zero Energy Building produces at least as much energy as it uses in a year, when accounted for at the site. • __Net Zero Source Energy__**:** A source Zero Energy Building produces at least as much energy as it uses in a year, when accounted for at the source. Source energy refers to the primary energy used to generate and deliver the energy to the site. To calculate a building’s total source energy, imported and exported energy is multiplied by the appropriate site-to-source conversion multipliers. • __Net Zero Energy Costs__**:** In a cost Zero Energy Building, the amount of money the utility pays the building owner for the energy the building exports to the grid is at least equal to the amount the owner pays the utility for the energy services and energy used over the year. • __Net Zero Energy Emissions__**:** A net-zero emissions building produces at least as much emissions-free renewable energy as it uses from emissions-producing energy sources.

Net Zero Site Energy is a 1:1 offset that has fewest external fluctuations. These types of buildings would utilize photovoltaic cells and hot water heaters. Small wind power, low impact-hydro, and parking lot PV systems are site specific.

Net-Source Energy is about a 3:1 ratio, in to out. These buildings produce as much energy as they use when measured at the source. Source energy can be determined by multiplying both imported and exported are multiplied by the appropriate site-to-source energy factors. Power generation and transmission factors are needed. These energy factors are site and region specific. Regional Time-Dependent Valuations for determining the time-of-use source energy was offered as one way to account for variations.

Net Zero Energy Cost Buildings are the hardest to achieve, they produce more than their buildings needs and are reimbursed enough to offset energy fees, distribution fees, peak demand, taxes, metering changes for electricity and gas. These buildings usually adapt their fuel types with the changing metering prices. A Zero Energy Cost building may be zero cost one year but not the next due to metering prices.

Net Zero Emission buildings create enough renewable energies on-site to offset emission-producing energies it also requires. Achieving Net Zero Emission can be accomplished by purchasing emission offsets from other sources; these sources are area specific and need to be considered when purchasing energy offsets.

Achieving a Zero Energy Building Is especially hard for larger buildings. These buildings need to drastically reduce energy use while implementing the right design towards their building. The definition of what Zero Energy Building a site want is site specific and critical for the design and management.

The management of a Zero Energy Building is crucial. Understanding the energy use of a building, specific fuel metering charges, as well as how the building is performing are all vital parts of the management process. A Zero Energy Building, at any level, needs a very strict energy management plan.


 * The Aiken Center**

The Aiken center is a now a very different building. The renovations utilized new energy efficient windows, insulation, including the solarium, green-roof insulation, as well as building insulation. My guess is that more efficient heating and cooling systems were installed during this renovation as well. Ambient light is utilized throughout most of the rooms to utilize the suns light and reduce electricity consumption. The Eco-Machine uses a contained ecosystem to purify water and recycles it through the buildings grey water, reducing potential energy costs. This water eventually makes it to the wastewater treatment center and is treated, using energy and costing money. These are all giant leaps forward towards a fully sustainable building. This paper was geared towards the sheer energy consumption of a building, and that buildings ability to pay back, or get paid for, its energy.

Aiken, like all buildingts on campus receive its heating from the central heating plant. I’m speculating, that Aiken is attached to the UVM regional grid that is then attached to Burlington electrics grid. The Aiken center has drastically reduced its energy use, but has done little to nothing, that I know of, for producing energy. Of course this is a fresh/ new renovation and there may be future plans for solar panels. However, this building is geared towards education; the green-roof will prove to be more useful towards education than a solar panel based rooftop. This paper fails to take into account energy sources other than that of the power-plant. This was inevitably because the paper was developed for the U.S government Dept. of Energy as a base to establish an aggressive plan towards creating technology and knowledge base for cost-effective-zero-energy commercial buildings by 2025.

More research needs to be done into what the Aiken centers usages are, the sustainability department and what fraction of offsets Aiken is issued, if any.

While this is clearly one of the most sustainable buildings in the Country there are room for improvements and innovative designs to further capture energy that is wasted.

Some ideas to further reduce energy at the Aiken center would be to install Solar PV panels on a section of the roof, or create a Solar Hot water heater.

Our P3 groups should have some innovative ideas that could help Aiken become a ZEB.

More Research is needed to determine how Aiken could become a sustainable building, producing knowledge while preserving the environment.

-We could probably offset out energy use by buying alternative energy credits.

-It would be interesting to see Aiken Energy use before and after renovations.