HEATING + COOLING


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HEATING + COOLING


GENERAL INFORMATION


GENERAL INFORMATION


WHEN TO USE THIS BASIS OF DESIGN SECTION:

This BOD section should be used for new construction projects and for any projects involving work on the heating or cooling mechanical equipment. Upgrading a building's heating and cooling equipment presents opportunities to improve the building utility performance. This section is intended to outline criteria for heating and cooling systems in rehab and new construction projects.

Heating and Cooling.jpg
 
 

TYPES OF HEATING AND COOLING


TYPES OF HEATING AND COOLING


HEATING:

BOILERS WITH FAN COIL UNITS (WHALEN UNITS)

INDIVIDUAL DUCTED FURNACES

INDIVIDUAL HEAT PUMPS WITH DUCTED UNITS

INDIVIDUAL HEAT PUMPS WITH NON DUCTED CASSETTES

CENTRAL HEAT RECOVERY HEAT PUMP SYSTEMS (VRF) WITH DUCTED AND NON-DUCTED UNITS.

COOLING:

THROUGH WALL ACS

CHILLERS

HEAT EXCHANGERS ON FURNACES WITH OUTDOOR CONDENSERS

HEAT PUMPS (INDIVIDUAL AND CENTRAL)

 

Controls:

IN-UNIT

CENTRAL

 

BOILERS WITH BASEBOARD RADIATORS


BOILERS WITH BASEBOARD RADIATORS


BOILERS WITH BASE BOARD RADIATORS (hydronic)

  • Pros: quiet distribution with no drafts, or dust moving through the air

  • Cons: provides heat, but no air conditioning

bOILERs:

Fuel: natural gas or oil.
Location: central mechanical room(s)
How it works: The boiler burns fuel to heat water (or an antifreeze solution) to a desired temperature for distribution. Once the water is hot enough for distribution, it is supplied through piping to spaces that need heat. Meanwhile cooler water that has already released its heat in a space is returned to the boiler so it can be reheated. 

When replacing:

  • Emergency: replace in kind.
  • End of service life: consult with Design + Building Performance Department to maximize energy efficiency.

Energy Efficiency Measures:

Condensing Boilers can run at over 95% efficiency: When possible, direct-vent modulating-condensing boilers should be used since they increase energy efficiency by capturing the extra heat in the flue gas condensation that is typically exhausted from the building. These boilers also modulate their burner according to demand, instead of simply turning it on and off, which increases the boiler's efficiency. Direct-vent boilers are also sealed combustion, meaning they pull fresh air from outdoors, and can exhaust back to the outdoors through a simple PVC pipe, instead of through a masonry chimney.  

Things to note:

  • A boiler can provide both heat and hot water: A boiler can be paired with an indirect water heater to provide both heat and hot water with only one heating device; the boiler. The boiler heats a coil within the water heater tank, which heats water that is then piped to both radiators, and showers and sinks.
      Direct-vent modulating-condensing boilers

    Direct-vent modulating-condensing boilers


     

    circulator PUMPS:

    Fuel: electricity
    Location: central mechanical room(s)
    How it works: Pumps help deliver the hot water to spaces of on upper floors, or on opposite ends of the building from the mechanical room. 

    When replacing:

    • Emergency: replace in kind.
    • End of service life: consult with Design + Building Performance Department to maximize energy efficiency.

    Energy Efficiency Measures:

    "Smart" variable-speed pumps can reduce pump energy by 80%: When possible, "smart" variable speed pumps with ECM motors should be used since they increase energy efficiency by monitoring demand and throttling the pump speed up and down accordingly, instead of running continuously 24/7. 
        "Smart" variable-speed circulator pumps

      "Smart" variable-speed circulator pumps


       

      DISTRIBUTION:

      Fuel: none
      Location: in spaces requiring heat
      How it works: Piping carries hot water from the boiler to other areas of the building, and eventually to radiators that distribute the heat to the space. Radiators are typically located along the base of exterior walls and below windows. As hot water from the boiler passes through the radiator, the heat is transfer to the radiator's many thin metal fins, which in turn heat the air surrounding the radiator. 

      When replacing:

      • Emergency: replace in kind.
      • End of service life: see energy efficient measures below.

      Energy Efficiency Measures:

      can't find more efficient versions of hydronic baseboard heaters that work with centralized system. 
        Hydronic baseboard

      Hydronic baseboard


       

      CONTROLS:

      Lots of existing multifamily buildings with boilers aren't able to adequately control the temperature in each apartment, meaning residents often open windows to "control" the temperature because the boiler is over heating the units.   

      Typically the problem is due to:

      • No zone/apartment level control, or
      • Non-electric thermostats on radiator valves
      • Also, central boiler system resets hot water based on ONLY outdoor temperature

      Energy Efficiency Measures:

      Use wireless thermostats in each space that:
      1) Measure the ambient temperature of the space,
      2) communicate with the space's relevant zone valve,
      3) and communicate with the central boiler controls. 
      Use wireless radiator zone valves that:
      1) communicate with the thermostats and central boiler controls, 
      2) and are centrally controlled, based on the thermostat's reading of ambient temperature.
      ** If feasible, zone valves should be installed at each unit. Otherwise, install zone valves at each riser.
      Use wireless boiler controls that:
      1) communicate with the thermostats and zone valves, 
      2) and supply heat based on both apartment and outdoor temperatures.
        Central Boiler Controls

      Central Boiler Controls

        Wireless Thermostat

      Wireless Thermostat

        Wireless Zone Valves

      Wireless Zone Valves