Docstoc

unitary

Document Sample
unitary Powered By Docstoc
					NRCan > OEE > Heating, Ventilation and Air Conditioning

Business: Industrial
Heating, Ventilation and                                                HVAC
Air Conditioning                                                        How Much Will I Save?
                                                                        Purchasing Tips

High-Efficiency Unitary                                                 Useful Links
                                                                        Back to Products
Air-Conditioning Units
(19 to 73 kW)
Unitary air-c onditioning units are self-c ontained and are c ommonly sold "off the shelf," either as
a single packaged unit or as a split system (see insert).

High-efficiency unitary air-conditioning units provide the same reliable space cooling as standard
effic ienc y models, but they use up to 25 percent less elec tricity. That's good for your company,
and it's good for the environment. Reducing electricity use saves money, and improving energy
effic ienc y reduces greenhouse gas emissions that contribute to climate change.

 Air-Conditioning Terms

        A unitary air-conditioner is a factory-made assembly that normally includes an
        evaporator or c ooling coil and a compressor and c ondenser c ombination. Unitary
        systems with one factory-made assembly are called single package systems; those
        with more than one assembly are called split systems.
        Energy Efficiency Ratio (EER) is a measure of full-load effic ienc y; the higher the EER,
        the more efficient the unit. EER represents the ratio of total cooling capac ity (Btu/h)
        to elec trical energy input (watts).
        Integrated Part-Load Value (IPLV) is a seasonal effic ienc y rating that applies to
        units with stated partial capac ities, such as units with staged compressors.
        1 ton = 12 000 Btu/h = 3.516 kW


This technical note, prepared by EnerGuide for Industry, addresses unitary air-conditioning
units sized from 19 to 73 kW (5.4 to 20 tons), the most widely used type of air-conditioning
system in industrial and c ommerc ial fac ilities.

High-efficiency air-c onditioning units incorporate a number of features to reduc e elec tricity
consumption. These inc lude

      Condenser. The c ondenser may be made larger to reduc e the c ondensing temperature
      and c ompression ratio.
      Condenser fans. Propeller fans are sized and shaped for efficient operation at full and
      part load.
      Filters and cooling coil. Coils and filters are larger to reduce the airflow veloc ity and
      improve heat transfer. They are also designed to have easy acc ess for c leaning.
      Economizer. Reliable damper controls ensure that maximum use is made of free outside
      cool air, whenever available. As well, low-leak dampers keep out unwanted air when the
      dampers are closed.
      Supply-air fan. High-efficiency airfoil blades are used with an effic ient motor and
      adjustable speed drive (ASD).
      Compressors. Multiple compressors may be used and sized to provide efficient operation
      at part-load.

Currently, unitary air c onditioning units (19 to 73 kW) sold in Canada are regulated by Canada's
Energy Effic iency Regulations and are required to meet minimum efficienc y levels as spec ified in
the Canadian Standards Association's CSA C746-98, Performance Standard for Rating Large Air
Conditioners and Heat Pumps. (These regulations are c urrently under review.) In accordance
with c ommitments made under the Montreal Protoc ol, the use of HCFC-22 as the refrigerant in
unitary air-conditioning units will be phased out in new equipment by 2010.

A number of manufac turers provide high-efficiency air-conditioning models that have signific antly
higher EERs than the minimum levels required under Canada's Energy Effic ienc y Regulations.
ENERGY STAR® is a voluntary labelling program that has worked with manufac turers to develop a
set of specifications that enables buyers to identify these high-efficiency models. Table 1
belowillustrates the improved energy efficiency of an ENERGY STAR unit and the best available
unit c ompared with a typic al standard air-c onditioning unit in two size ranges.

                                           Table 1
      Canada's Energy Efficiency Regulations Minimum Efficiency versus ENERGY STAR
                Efficiency Specifications for Large Unitary Air Conditioners

                                                                                                    Best
 Capacity         Energy Efficiency Regulations                ENERGY STAR Efficiency
                                                                                                  Available
  (kW)                Minimum Efficiency                           Specifications
                                                                                                    Unit
                                8.9 EER;                                11.0 EER;                 13.4 EER;
  19 to 40
                                8.3 IPLV                                11.4 IPLV                 13.9 IPLV
                                8.5 EER;                                10.8 EER;                 13.1 EER;
  41 to 73
                                7.5 IPLV                                11.2 IPLV                 14.1 IPLV

  E-Source Cooling Technology Atlas

   ibid Note that the minimum efficiency regulations of Natural Resources C anada's Office of Energy Efficiency
 are scheduled to be updated to match ASHRAE 90.1-1999. The new minimum efficiencies will regulate units in
 the range of 19 to 40 kW to have ratings of 10.3 EER and 10.6 IPLV, and units from 41 to 73 kW will have
 ratings of 9.7 EER and 9.9 IPLV as their minimum efficiencies.


EnerGuide for Industry is an initiative of Natural Resourc es Canada's Office of Energy
Effic ienc y. Its objective is to provide the industrial-equipment procurement community with
information and decision-making tools that will help them to improve their company's profitability
while contributing to Canada's energy effic iency and environmental objec tives. This technical
profile is part of a series; other produc ts profiled include elec tric motors, electronic high-
intensity discharge (HID) ballasts and dry-type transformers.

                                                                                Next: How Much Will I Save?




Date Modified: 2009-05-08

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:5
posted:7/26/2012
language:English
pages:2