Variable Refrigerant Flow (VRF)

Variable refrigerant flow (VRF) is an HVAC air source heat pump technology.  VRF uses refrigerant as the cooling / heating medium, and allows one outdoor condensing unit to be connected to multiple indoor evaporators, each individually controllable by its user, while modulating the amount of refrigerant being sent to each evaporator. By operating at varying compressor speeds, VRF units work only at the needed rate. Heat recovery VRF technology allows individual indoor units to heat or cool simultaneously as required, while the compressor load benefits from the internal heat recovery. Certain systems allow heat to be harvested from one zone and delivered to another zone further reducing the load on the condenser. Energy savings of up to 55% are predicted over comparable unitary equipment.

Variable Refrigerant Flow (VRF) is a technology introduced as a system to minimize efficiency losses found in conventional HVAC systems and provide sustainable energy benefits. An air source VRF system is engineered to minimize or use no ductwork, and save on the cost of large distribution fans, multiple water pumps operation and water piping.  On certain systems up to 20 indoor units can be connected to each outdoor unit, producing a total applied capacity of up to 150% of the outdoor unit's rated capacity.  Energy efficient and easy to design, install, and maintain, a VRF system has the lowest life cycle cost of any system on the market today.

Air Sealing - High Performance Building

Infiltration, or air leakage through the exterior building skin, is one of the major energy losses in most buildings.  Therefore, proper air sealing is an essential strategy for a successful high performace building.  As buildings get tighter, however, combustion air from gas appliances and the off-gassing of chemicals from interior finish materials must be exhausted mechanically and fresh make-up must be carefully introduced into the occupied spaces of the building without creating any cold drafts.  Combined with heat recovery ventilation systems, air sealing can improve the comfort of interior environments while not sacrificing indoor air quality.  The proper location and installation of air barriers and thermal insultaion in the building envelope, and detailing around all wall and roof penetrations need careful attention.  Understanding of basic building science is neccessary to properly integrate the air barrier, thermal barrier, and rain screen within the structure of a high performance building.  images by Marc Rosenbaum from his presentation at the NESEA conference in Boston, MA.

Rain Gardens - Stormwater Management

A rain garden is a planted depression that allows rainwater runoff from impervious urban areas like roofs, driveways, walkways, parking lots, and compacted lawn areas the opportunity to be absorbed. This reduces rain runoff by allowing stormwater to soak into the ground as opposed to flowing into storm drains and surface waters which causes erosion, water polution, flooding, and diminished groundwater. They can be designed for specific soils and climates. The purpose of a rain garden is to improve water quality in nearby bodies of water. Rain gardens can cut down on the amount of pollution reaching creeks and streams by up to 30%.

Native plants are recommended for rain gardens because they generally do not require fertilizer and are more tolerant of one’s local climate, soil, and water conditions, and attract local wildlife such as native birds. The plants — a selection of wetland edge vegetation, such as wildflowers, sedges, rushes, ferns, shrubs and small trees — take up excess water flowing into the rain garden. Water filters through soil layers before entering the groundwater system. Root systems enhance infiltration, maintain or even augment soil permeability, provide moisture redistribution, and sustain diverse microbial populations involved in biofiltration.  Also, through the process of transpiration, rain garden plants return water vapor to the atmosphere. 

Light Tubes or Tubular Skylights

Tubular Skylights can bring life into windowless spaces without the usual problems of condensation and heat loss associated with conventional skylights.  Not only do they save energy but with natural daylight building occupants sense the fluctuating light level when clouds pass by, offering relief from a feeling of being closed indoors and offering instead a connection with the natural world outside.  Studies have shown that productivity increases and sick leave drops off in work spaces with natural lighting.  Commercial business owner's have discovered that products displayed in areas with natural lighting are perceived to be more attractive to consumers and actually sell better than items displayed in areas with artificial lighting.

Insulating Concrete Forms (ICF's)

Insulating Concrete Form (ICF) is a system of formwork for concrete that stays in place as permanent building insulation for energy-efficient, cast-in-place, reinforced concrete walls, floors, and roofs.  The polystyrene forms are interlocking modular units that are dry-stacked (without motar) and filled with concrete. The forms lock together somewhat like Lego bricks and serve to create a form for the structural walls or floors of a building.  Nailing strips embedded in the forms facilitate attachment of interior and esterior finishes.  ICF construction is becoming increasingly commonplace for both low rise commercial and residential construction as more stringent energy efficiency and natural disaster resistant building codes are adopted.  ICF's have many advantages over conventional construction:

Energy Efficiency

•  Minimal, if any, air leaks, which improves comfort and reduces heat loss compared to walls without a solid air barrier.

•  High Thermal resistance (R-value) typically above R-20;  This results in saving energy compared with uninsulated masonry. 

•  Continuous Insulation without Thermal Bridges or 'insulation gaps' as is common in framed construction.

•  Thermal mass, when used well and combined with passive solar design, can play an important role in further reductions in energy use, especially in climates where it's common to have outside temperatures swing above inside temperatures during the day and below at night.

Strength and Durability

•  Insulating Concrete Forms create a structural concrete wall that is up to 10 times stronger than wood framed structures.

•  Structural integrity for better resistance to forces of nature, compared with framed walls.

•  Concrete and Polystyrene do not rot when they get wet.  However, polystyrene must be protected from boring insects and rodents by appropriate means.

Sound Absorption

•  ICF walls have much lower rates of acoustic transmission. Standard thickness ICF walls have shown sound transmission coefficients (STC) between 46 and 50 compared to 36 for standard fiberglass insulation and gypsum walls.

Plains Animal Hospital New and Improved Facility

A truly great addition to our area has come via the Plains Animal Hospital/Northeast Veterinary Referral Hospital and their brand new facility that employs sustainable design techniques. After 10 years of planning, Douglas Ayers idea to build the first green animal hospital and specialty animal care unit in the

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