Sunday, 19 February 2012

Almost Zero Energy – Michigan LEED Home give 2011 Energy Report (Owners Report)

As of October 2010 the Jay & Liz McClellan home officially earned a LEED Platinum rating, which is the highest of 4 levels of certification offered by the USGBC. They achieved a HERS index of 20, which one of the best in the state of Michigan.

This summarizes the building's energy production and consumption for calendar year 2011.


Solar electricity produced: 6033 kW h (16.5 kW h per day)
Electricity consumed: 6150 kW h (16.8 kW h per day)
Non-heating: 5350 kW h, heating: 800 kW h
Net electricity deficit: 117 kW h (-2%)

Owners Report: Our first 12-month report started April 1 2010 when we first activated the PV system and went through April 1 2011, but this report covers calendar year 2011 so there are a few months of overlap. For calendar year 2011 we fell just short of our goal to produce more electricity than we consumed, with a net deficit of 117 kW h for the year. Compared to our first 12 months of operation, average daily production dropped by 0.3 kW h but consumption increased 1.8 kW h. Some of that is due to having an additional family member living here since mid-year, and some is due to adding an upright freezer that uses about 1 kW / day.

Below is a graph showing the inside (red) and outside (blue) temperatures that we recorded throughout the year. Overall the house was very comfortable, with just a few days in the upper 70s during some hot summer weather when allergies made us reluctant to open up the house at night since our ventilation system filters out pollen from the incoming air.

The graph below shows the heat storage tank temperatures over the year. The big gap is when we drained the tank due to a leak, and we were able to get the tank warmed up again in the fall but not to the degree we would have liked.

Here is a list of some of the features of our home that qualify for LEED credits. This is not an exhaustive list, just some of the more interesting features:

  • Universal Design - every room in the home is usable by persons with limited mobility
  • Limit conventional turf - we will have no conventional turf at all, just gardens surrounding the house
  • Reduce irrigation demand - all our permanent plantings will have far less water demand than typical landscaping in this region
  • Water reuse - our rainwater harvesting system collects water from more than 50% of our roof, to be used for watering the gardens and flushing toilets
  • Indoor water use - all our toilets, lavatories and showers have very high efficiency fixtures that use much less water than conventional fixtures
  • Optimize energy performance - our home is designed to generate more energy than it consumes, using a combination of superinsulation, energy efficient appliances, active and passive solar heat collection, and solar electric generation
  • Construction waste reduction - our construction will generate about 1/10th as much waste per square foot as a typical home construction
  • Combustion venting - our wood stoves are EPA certified for low emissions, and have an outside combustion air supply to avoid drawing warm air from the house
  • Outdoor air ventilation - we use a heat recovery ventilator (HRV) to provide continuous ventilation, and to recover about 70% of the heat from the outgoing stale air
  • Local exhaust - our bathrooms are equipped with humidity sensors, which will increase the airflow through the HRV whenever excess humidity is present
  • Air filtering - the ventilation air intake is equipped with a high efficiency air filter (rated MERV 13) to reduce particulates in the incoming fresh air
  • Indoor contaminant control - we have a shoe removal and storage space near the front door, and a central vacuum system that exhausts to the outside

In addition, here are some of the environmentally preferable products in our home that earn LEED credits:

  • Floor - polished concrete generates far less emissions and traps far less dirt than carpet
  • Walls & ceilings - our drywall was made less than 200 miles away from 96% recycled material
  • Paints - All walls and ceilings use zero-VOC paint
  • Countertops - we're making our own countertops using recycled glass
  • Insulation - our cellulose wall insulation is about 85% recycled paper

Source: Alliance for Environmental Sustainability & Jay & Liz McClellan Homepage

Illinois Net-Zero-Energy masterpiece producing 40 percent more energy than it consumes

Starting with an eco-conscious dream for a truly green home transformed owner Michael Yannell’s Chicago residence into a $1.6 million, two-story 2,675-square-foot, four-bedroom and two-bath Net-Zero-Energy masterpiece, producing 40 percent more energy than it consumes.

Completed in 2009, it is not only Chicago’s first LEED Platinum-certified home, but it has scored higher than any other LEED-certified project in history. Architect Farr Associates, builder Goldberg General Contracting Inc. and engineering MEP firm dbHMS created this urban infill project to utilize aspects of alternative energies through passive solar, solar grid technology, a greywater system and closed looped geothermal heating and cooling components. According to owner Michael Yannell, the main goal of this project was to create a more energy- and water-efficient, environmentally conscious place to live and to set an example by building a home as sustainable as possible. Incidentally, the green materials generally were no more expensive than conventional alternatives.

This Net-Zero-Energy residence was built using the U.S. Green Building Council’s (USGBC) LEED for Homes Pilot Program regulations. In order to earn the coveted LEED Platinum-certification, a project must meet the 100-point requirement, in which the Yannell residence scored 115.5. According to Net-Zero statistics, the Yannell residence generates 18,000 kWh/yr and uses only 12, 689 kWh/yr, earning the Yannell property an approximate $52,000 in tax credits in 2008-2009.

According to Jonathon Boyer, principal and director of architecture for Farr Associates, the permit and design processes were a challenge from the beginning, but thanks to help from a hand-picked team, deadlines were met and the project was a success.

“We put together a team of engineers, contractors and a landscape architect, and the entire project was a team effort,” Boyer said. “Building Net-Zero-Energy is very difficult, and it requires cooperation between all components and consultants. We believe we’ve broken the sound barrier with this house, especially in the Chicago area.”

This being the first LEED-certified home came with obstacles along the way. According to Boyer, by creating new systems such as the greywater system, which recycles water used from the toilets for the washing machine, it was tricky trying to solidify the permit process. It has opened up new options for Chicago to consider when building more sustainable homes.

“It was a learning process, the city of Chicago was open to it. We didn’t have any hard and clear standards in the city for permitting this kind of system,” Boyer explained. “As a result of this house, the city of Chicago Committee of Standards and Tests is adopting a new state / city code for rainwater / greywater reuse. “We were pioneers and induced the city to think about changing permits to use more sustainable elements into the residential market,” Boyer said.

Other than utilizing alternative energies, the Yannell residence’s modern design integrated into the traditional neighborhood fuses form with function in a dense infill space. The home was built on a recycled lot where the previous building could not be salvaged. Boyer explained that typically energy-efficient homes are bland and lack style, but in this case, the owner and the building team wanted something well-designed and unique.”He [owner, Michael Yannell] wanted something aesthetically compelling and functional,” Boyer said.

The floor plan is designed as a dual-wing connected by a foyer, which acts as an entry and passageway, both equipped with south-facing windows to utilize natural light and garden views. The positioning of the wings help compete with the Midwestern climate year-round. With temperatures ranging from the high 90s in the summer to blistering zero-below winters, it was crucial to find the most sustainable design possible. Each wing has a uniquely shaped multi-functional V-shaped green-roof designed for stormwater management and for concealing the 48 photovoltaic grids on the home. “The

butterfly pattern roofs are designed to screen the solar panels from view, while providing an ideal angle for the panels to harness the sun’s energy,” Boyer said. Although the Yannell residence has received the highest LEED score, the materials it took to achieve the title are not unattainable for other eco-conscience projects. According to Boyer, “LEED for Homes is less than $3,000 for certification.” In this case, it assisted in the construction process by acting as a detailed guide when installing aspects such as air quality, water systems and when planning the positioning.

Although there is no set specific standard definition for a Net-Zero- Energy home, Boyer said that there are other homes out there that claims to be Net-Zer-Energy, but many have only lowered their energy consumption. Only the Yannell property has the data to back it up. According to Principal of MEP firm dbHMS, Sachin Anand, “It’s [the Yannell residence] the future of housing and power generation where each home is a greenhouse emission-free power plant.”

Source: Alliance for Environmental Sustainability

Thursday, 9 February 2012

Carbon Footprint Calculator

Heat Island

What Is a Heat Island?

Heat islands are characterized by urban air and surface temperatures that are higher than nearby rural areas. Many U.S. cities and suburbs have air temperatures up to 10˚ F (5.6˚ C) warmer than surrounding natural land cover. The heat island sketch below shows a city's heat island profile. It demonstrates how temperatures typically rise from the urban-rural border, and that the warmest temperatures are in dense downtown areas. On the other words heat island is the presence of any area warmer than its surrounding landscape. They can be developed on urban or rural areas. As it would be expected, there is a relatively minor knowledge about non urban heat islands, since they usually do not represent a risk for the human being or the environment. Meanwhile, urban heat islands have been profusely addressed during decades in urban areas with a wide range of climates and landscapes.

Heat islands are often largest over dense development but may be brokenup by vegetated sections within an urban area.

What Causes Heat Islands?

Heat islands form as cities replace natural land cover with pavement, buildings, and other infrastructure. These changes contribute to higher urban temperatures in the following ways:

•Displacing trees and vegetation minimizes the natural cooling effects of shading and evaporation of water from soil and leaves (evapotranspiration).

•Tall buildings and narrow streets can heat air that is trapped between them and reduce wind flow.

•Waste heat from vehicles, factories, and air conditioners may add warmth to the air, further increasing temperatures.

Heat islands are also influenced by a city’s geography and prevailing weather conditions. For example, strong winds and rain can flush out hot, stagnant air from city centers, while sunny, windless conditions can exacerbate heat islands.

When Do Heat Islands Form?

Heat islands can occur year-round during the day or night. Urban-rural temperature differences are often largest during calm, clear evenings. This is because rural areas cool off faster at night than cities, which retain much of the heat stored in roads, buildings, and other structures.

Effects of Heat Island

The well-known phenomenon allusive to the atmospheric temperature rise experienced by any urbanized area. The heat island phenomenon has been commonly associated to cities, because their surfaces are characterized by low albedo, high impermeability and favorable thermal properties for the energy storage and heat release. Besides, many cities present narrow urban canyons with reduced sky view factors that tend to absorb and reemit the radiated energy from their surfaces. These factors contribute to urbanized areas increasing their temperatures in relation to their rural peripheries that are usually more vegetated, and therefore moderate the temperatures mainly through the evapotranspiration process, shades production and solar radiation interception.

How Do Heat Islands Affect Us?

Increased urban temperatures can affect public health, the environment, and the amount of energy that consumers use for summertime cooling.

Public Health: Heat islands can amplify extreme hot weather events, which can cause heat stroke and may lead to physiological disruption, organ damage, and even death – especially in vulnerable populations such as the elderly.

The Environment: Summertime heat islands increase energy demand for air conditioning, raising power plant emissions of harmful pollutants. Higher temperatures also accelerate the chemical reaction that produces ground-level ozone, or smog. This threatens public health, the environment, and, for some communities, may have implications for federal air quality goals.

Energy Use: Because homes and buildings absorb the sun’s energy, heat islands can increase the demand for summertime cooling, raising energy expenditures. For every 1°F (0.6°C) increase in summertime temperature, peak utility loads in medium and large cities increase by an estimated 1.5 – 2.0 percent. Cities in cold climates may actually benefit from the wintertime warming effect of heat islands. Warmer temperatures can reduce heating energy needs and may help melt ice and snow on roads. In the summertime, however, the same city may experience the negative effects of heat islands.

A brief definition of the main Heat Island types

Surface urban heat island: The remotely sensed urban heat island. It is observed by using thermal infrared data that allow to retrieve land surface temperatures. Usually, close relationships between the near surface air temperatures and land surface temperatures have been found. Therefore, the surface urban heat island is a reliable indicator of the atmospheric urban heat island.

Micro urban heat islands: They refer to urban hot spots as poorly vegetated parking lots, non-reflective roofs and asphalt roads. Micro urban heat islands are strongly affected by micro climate factors, therefore remotely sensed data are more suitable than atmospheric data for identifying heat spots.

Urban heat sink: Also called negative heat island. It is the expression of a city colder than their countrysides. There are few references about this phenomenon. Heat sinks have been observed in cities with temperate, tropical, semi-arid and arid climates, and mainly during the mornings.

United State Environmental Protection Agency
Urban Heat Islands.