HVAC and ERV Systems

Heating Ventilating and Air Conditioning

Energy Recovery Ventilation

 

 

THE BASICS

HVAC systems refer to the mechanical systems that heat, cool, ventilate, filter, humidify, or dehumidify air in a room or building. ERV’s are Energy Recovery Ventilators; passive and mechanical systems which help prevent energy loss. These systems come in many types and configurations, but can be commonly organized into the following categories:

  1. 1. Central or “all-air” systems, whereby a common or central air handling unit supplies heated or cooled air to multiple spaces/rooms in a building via a duct network.

  2. 2. Centralized fluid based systems, whereby a fluid, typically water, is circulated around a building to provide heating or cooling.

  3. 3. Decentralized or unitary systems, which consist of dedicated heating or cooling equipment for particular building spaces/rooms, such as packaged room air conditioning units or heat pumps. Our mini-SDHV systems are perfect for this.

  4. 4. Exhaust fan systems: kitchens, rest rooms, laboratories, industrial processes; also commonly installed in larger commercial office and industrial buildings.

Go here for more about Air Handling Systems

Systems We Use

    ● SDHV HVAC Systems

    ● Humidity control

    ● ERV / Passive & Mechanical

    ● Mini-chillers and heat pumps

    ● Natural gas (for heating in some circumstances)

    ● System Hygienics: Air purification

    ● Deodorization and Ambiance Control (Scented Air Systems)

    ● Grease vapor removal

    ● Tankless water heating (ELECTRIC on-demand local hot water)

    ● Passive Solar Air Heating

    ● Passive Air Ventilation / Circulation

 

OVERSIZING

There are numerous reasons why oversizing is a bad idea:

ⱶ   Oversized equipment costs more and requires larger electrical circuits

ⱶ   Oversized compressors have a shorter life expectancy

ⱶ   Excess capacity compromises comfort (larger temperature swings)

ⱶ   Excess cooling capacity compromises moisture removal, a big deal in humid areas

ⱶ   Larger compressors and blowers produce more noise

ⱶ   Excess capacity compromises indoor air quality (less run time = less filtration)

ⱶ   Excess cooling capacity increases the potential for structural damage from moisture

ⱶ   Oversized equipment is less efficient, thus increases operating costs

Said differently, right-sized HVAC systems cost less up front, last longer, provide better comfort, improve moisture removal, run quieter, provide better filtration, and cost less to operate.

Oversizing is endemic in code-built buildings and becoming an epidemic in high performance buildings. Even though most mechanical contractors have been taught the virtues of right-sizing, they can’t seem to break free from their ‘bigger is better’ bias.  

See: Gambit* or Piracy? Moreover, most are unfamiliar with the nuances of designing for high performance buildings. As a result, the HVAC equipment is often grossly oversized. This not only undercuts potential energy savings but makes these buildings especially vulnerable to comfort and moisture problems.

The best way to ensure proper sizing is to size the equipment according to Manual J procedures. To this end, ABCS utilizes load calculations in conjunction with Energy Star, LEED and BPI or our customized building performance programs. Builders who understand the rationale for right-sizing appreciate the value of this service. Moreover, properly prepared load and equipment specification makes it easier for ABCS to show the builder and/or building owner why we’re recommending certain systems.

Air movement keeps you cool by increasing the rate at which moisture evaporates from your skin. There are two main ways to passively harness air movement:

1. Orient your home to catch the prevailing breeze

2. Use passive ventilation to get air circulating

Passive ventilation uses doors, windows, vents, louvers and other openings to let fresh air into and through your home.

This helps to provide cooling, as well as removing moisture and airborne pollutants.

You’ll need more air movement as humidity increases.
 

Our Passive Air System

● Assumes no shade exists – (which may further aid cooling)

● Fresh air from outside goes through a control system – (when windows aren’t open)

Cooling air with water. When water evaporates, it absorbs heat from surrounding air, so the air cools. Evaporation works best when humidity is lower so the air can take up more water vapor. Rates of evaporation are increased by air movement and the exposed surface area of water.

Fountains and mist sprays are effective for cooling, so if practical and feasible, they should be integrated into the exterior environmental design.
 
 

Heating Water & Radiant Flooring

Water heating, which we accomplish more effectively now with PVC photo-voltaic cells – can double as a heat source for the HVAC SDHV system. We also use it for Radiant Flooring systems which warms objects, animals and people – not the air… exactly, that is.

Please see the sections on Passive Water Heating & Radiant Flooring Systems.