Sustainable Lighting Design

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What is It?


  • A brief description of what it is.
  • If it is part of a system-level pattern put a link to it in here.
  • Also known as:

Why is it Important?


Describe how it:

  • strengthen our relationship to the earth...all are connected (sun, wind, water, plants and animals)
  • helps restore the planet's eco-systems (plant, animal, water, air)
  • builds strong communities.
  • creates equal economic opportunities and energy.
  • creates One Earth patterns of living

When to Use It?


  • List the important considerations when to use this pattern.
  • When would it be sustainable?
  • When would it not be sustainable?

Green Garage Use of Sustainable Lighting Design


Sustainability Goals

The sustainability goals for the Sustainable Lighting Design are:

  • Provide 80% of lighting needs with daylight.
  • Prvide high efficiency task lighting only when and where needed to conserve energy.
  • Provide minimum 10 footcandles for safety.
  • Integrate emergency lighting with PV system.
Strategy

The major elements of our ventilation strategy were:

Conceptual Design
  • Most of the lighting will be supplied by daylight through SolaTubes and windows.
  • Only places that require task lighting, emergency lighting, outdoor areas, and places not lit by daylight will have artificial lighting.
  • Include pictures, drawings or videos(flickr)


A Pattern Language for Lighting

Daylighting

High Efficiency Lighting

Emergency Lighting


Supporting Science

Proposed Materials / Suppliers
  • Identify (via links and short description) the materials and suppliers we propose to use.
Development Story

The Sustainable Lighting - Development Story page contains many images and videos documenting the process used at the Green Garage to design, build and operate our ?? system.

Related Internal Links
  • Help people find other related Green Garage pages that may help them. Keep it tight.

Resources


Sustainability Goals

The sustainability goals for the Hybrid Ventilation System are:

  • Fully integrated natural-mechanical system to meet the air exchange requirements with 50% of the required energy coming from natural sources and 50% from high efficiency mechanical sources.
  • Meet 20 cfm per person or 800 cfm for the building.
  • Maintain the indoor relative humidity at 45% +/- 15%.
  • Connect the building and the occupants to the natural systems.
  • Ensure healthy indoor environment.
  • Allow components of the system to be bypassed when they don't contribute to these goals.
  • The system should be simple to maintain, adapt and control.

Strategy and Conceptual Design

Hybrid Strategy

The major elements of our ventilation strategy were:

  • The hybrid ventilation system at the Green Garage has three main components:
    • Earth Tubes / ERU - Air Exchanger
    • Natural Ventilation
    • Moisture Control
  • Put the passive and active components in a series with the passive first in line. Only after the passive component cannot meet the needs does the active turn on and meet the "net" remaining requirement.
  • Reduction in size requirements for the active equipment. It also runs less frequently since it's second in line to the natural system. Both of these reduce energy usage.
  • Select the highest-efficiency active methods available.
  • Adopt a "Topping Off" strategy where we keep the indoor temperature in a tight range and the system is always running and very low levels and just topping off the heat when needed and cooling when needed. This basically eliminates any night time setbacks, because they lead to heating surges (sometimes followed by cooling surges when the sun comes out and people occupy the building.)
  • Make sure we are addressing moisture in every component (i.e. latent energy).


Earth Tube / ERU - Air Exchanger Design

The Earth Tubes and Energy Recovery Unit are tightly integrated into the air exchange system. In general, the Earth Tubes and Energy Recovery Unit provide the year-round foundation for the building's ventilation. During a normal air exchange, the outdoor air will be brought in through the Earth Air tubes and will be pre-heated or cooled, then enter the Energy Recovery Unit where the outbound air will be used to heat/cool the inbound air, as well as dehumidify or humidify the air.

Winter Example:
Outdoor Air Temp: 0 F
Outdoor Air Relative Humidity: ??
Ground Temp: 45 F
Indoor Temp: 68 F
Earth Tubes - Air Temp Coming In: 0 F
Earth Tubes - Air Temp Coming Out: 23 F (Rule of thumb: air temp gain equals 1/2 of the difference between the air and ground temperatures with 100 ft of tubing.)
ERU - Air Temp Coming In: 23 F
ERU - Air Temp Coming Out: 55 F (assumes 70% efficient)
Summer Example:
Outdoor Air Temp: 90 F
Outdoor Air Relative Humidity: ??
Ground Temp: 57 F
Indoor Temp: 78 F
Earth Tubes - Air Temp Coming In: 95 F
Earth Tubes - Air Temp Coming Out: 86 F (Rule of thumb: air temp gain equals 1/2 of the difference between the air and ground temperatures with 100 ft of tubing.)
ERU - Air Temp Coming In: 86 F
ERU - Air Temp Coming Out: 80 F (assumes 70% efficient)

The powerful aspect of this design is the contributions of the Earth Tubes and Energy Recovery Unit components naturally increasing as as the building's demand for energy increases due to the very hot or cold weather. This is because as the difference between the ambient temperature (e.g. outdoor air temp) and the ground or indoor temperature increases, the energy contributions of the Earth Tubes and Energy Recovery Unit increase naturally.

Another benefit of placing the earth tubes in front of the ERU is that the the ERU is susceptible to freezing if the air temperature drops below 23F for more than two days in a row. It would be very unusual for this to happen with the earth tube pre-heating the air before it enters the ERU.

The attached chart shows the relative contributions of each component.


Natural Ventilation Design

Natural ventilation is expected to be able to assist in about 50 - 90 days per year during the spring and fall months. Clearly in the months of extreme weather, natural ventilation would make no contribution. Natural ventilation is provided by opening the building's windows. More information is available on our Natural Ventilation pattern page.


Moisture Control Design

We have attempted to control moisture in and through every component of the ventilation system. The two main areas are the dew point in the envelope systems and the control of humidity, especially in the summer. We are planning on using a pressure-based strategy to control the humidity. It is an approach that has come from the in-depth experience of one of the professionals who has contributed extensively to our Net-Zero Energy design. For more on moisture control please see our Moisture Control pattern page.


Integration and Control Design

Integrating all these components does require significant thought. Some of the controls will be manual (even behavioral) and some will be automated. The key integration areas are: