HVAC system selection

HVAC system Heat pump

Heating Systems:

Furnaces: Small Capacity Furnaces:40,000 BTU/h to 80,000 BTU/h.

  Medium: 80,000 BTU/h to 120,000 BTU/h, Large: 120,000 BTU/h and above                     

Boilers: Small Capacity Furnaces:40,000 BTU/h to 80,000 BTU/h.

Medium: 80,000 BTU/h to 120,000 BTU/h, Large: 120,000 BTU/h and above

 Large: Exceeding 300,000 BTU/hr (approximately 88 kW)

 Heat Pump,

 Small Capacity: Small 1.5 tons to 3 tons. Medium: 3 tons to 5 tons, Large: 5 tons to 10 tons

 Variable Capacity Heat Pumps, Geothermal Heat Pumps.

Sub Category:

Hydronic Radiant Floor Heating & Modular Systems, BTUs/hr, Medium to Large, 50000 to 100,000 BTUs/hr,

Cooling Systems

Evaporator cooler -HVAC

• Air Conditioners,

Small Capacity (Under 12,000 BTU/h or 1 Ton), Medium Capacity (12,000

18,000 BTU/h or 1 - 1.5 Tons), Standard Capacity (18,000 - 24,000 BTU/h or 1.5 - 2 Tons), High Capacity

(24,000 - 60,000+ BTU/h or 2 - 5+ Tons).

 • Heat Pumps,

Small Capacity: 9,000 BTU/hr to 18,000 BTU/hr Medium Capacity: 18,000 BTU/hr to

36,000 BTU/hr , Large Capacity: 36,000 BTU/hr and above (3 tons and above)

 • Ductless Mini-Split Heat Pumps,

 BTU/hr for very small rooms or areas to over 60,000

• Geothermal Heat Pumps, 1.5 tons to 5 tons or more, depending on the size of the property.

• Evaporative Coolers, Small to Medium-Sized:1,000 to 3,000 CFM, Large-Sized: 6,000 CFM or more

• Hydronic Cooling, Are less common, from few thousand BTU/hr for smaller homes or individual

rooms to tens of thousands or even over a hundred thousand BTU/hr for larger homes.

Hydronic Systems:

 • Hydronic Baseboard Heating,

Hydronic Fan coil - HVAC

3,000 BTU/hr for smaller units designed for individual rooms to

over 10,000 BTU/hr for larger units

 • Hydronic Fan Coil Units,

Heating Capacity, 5,000 BTUs per hour to 30,000.

Cooling Capacity, 12000 BTUs to 60000 BTUs or more

• Radiators, Small Capacity:

1000 BTU/hr to 5,000 BTU/hr Medium Capacity: 5,000 BTU/hr to

15,000 BTU/hr , Large Capacity: 15,000 BTU/hr to 50,000BTU/hr.

 • Hydronic Heat Exchangers,

not used as the primary source of heat in residential settings.

HVAC systems categorize for application:

There are three categories for HVAC system

 • High-Rise Buildings

 • Low-Rise Buildings

 • Commercial Spaces

High-Rise Buildings:

•Chill Towers,

Chiller tower - HVAC

Small-Scale: 2-5 TR to 50-100 TR, Medium-Scale: 100-500 & 1000-5000 TR, Large-Scale: 5000 to 50000 TR

•Chilled Water Systems,

Residential and Small-Scale: fraction of a ton (a few kW) to a few tons (tens of kW), Commercial and Institutional Buildings: few tons to several hundred tons, Industrial and Large-Scale: several hundred tons to several thousand tons.

•Vertical Fan Coil Units (VFCU),

Small Capacity: 1,000 to 5,000 BTU/hr, Medium Capacity:  5,000 to 15,000 BTU/hr, Large Capacity: exceeding 15000 BTU/hr

•Heat Recovery Ventilation (HRV) Systems (Residential ):

50 CFM to 150 CFM, Medium Residential: 150 CFM to 300 CFM, Large Residential: 300 CFM to 600 CFM.                               

•HRV Systems: Small Commercial: 600 CFM to 1,500 CFM , Medium Commercial: 1,500 CFM to 5,000 CFM ,Large

Commercial: 5,000 CFM to 20,000 CFM or more

Variable Air Volume (VAV) Systems: Residential HRV Systems:1 to 20 Tons, Medium Residential: 20 to 100 Tons, Large Residential: 100 Tons to several thousands Tons.

 • VRF Systems: Cooling Capacity: 6 to 96 tons (72,000 to 1,152,000 BTU/hr). Heating Capacity: Similar ranges.

High Rise building heating:

Boilers:

 • Small to Medium Capacity Boilers:

100,000 BTU/h (29 kW) to 1,000,000 BTU/h (293

kW). Medium to Large Capacity Boilers: 1,000,000 BTU/h (293 kW) to 10,000,000 BTU/h (2,930 kW)

or more Multiple Boiler Systems: In larger high-rise buildings, multiple boilers may be installed to

meet the heating demand more efficiently. These boilers can be arranged in cascades or modular

configurations to provide redundancy and flexibility in operation.

 • High-Efficiency Condensing Boilers:

Small to Medium Applications: Capacity Range: 50,000 to 500,000 BTU/h.  

Large Applications: Capacity Range: 500,000 to 5,000,000 BTU/h, Often used as centralized systems in high-rise buildings to handle extensive heating loads.

Commercial and District Systems: Capacity Range: 5,000,000 to 12,000,000 BTU/h (or higher)Typically found in extremely large high-rise complexes or district energy systems.

• Combined Heat and Power (CHP) Systems:

HVAC CHP System

Electricity Generation, Waste Heat

Recovery, Thermal Applications, System Integration and Control, Benefits: total efficiencies of 70% to

90%, Reduced energy costs, Reduced energy costs, Environmental benefits, Enhanced reliability.

Low-Rise Buildings:

Packaged HVAC Units:

Residential Packaged:1.5 Tons to 5 Tons, Commercial Packaged: 3 to 25 Tons,

Medium to large, 25 to 100 Tons. Industrial Packaged: several hundred tons to several thousand tons.(Packaged

HVAC units are typically installed outdoors on the roof or ground level, which helps save indoor space and reduces noise levels inside the building.)

 • Below are available in both regular and Heat Pump options:

 • VRF Systems:

Small: 0.5 to 3 tons, Medium: 3-15 tons, Large: 15-60 tones. Both VRF heat pump and regular

VRF are comparable in terms of efficiency.

 • Central air conditioning systems:

Small Capacity: 1.5-5 Tons cooling, Medium Capacity: 5-10 Tons,

Large Capacity: exceeding 10 tons. are commonly used in larger buildings such as offices, commercial spaces, schools, hospitals, and high-rise buildings.

• Split Systems: not Heating capability in regular(heat pumps are capable):

1. Residential Split Systems { Small Capacity:0.75 – 1.5 Tons, Medium Capacity: 1.5 – 3 Tons, Large Capacity: 3-6 Tons.}

2. Commercial Split Systems {Light Commercial:2-5 Tons, Larger commercial: 5-20+ Tons}. Industrial Split Systems:

(20+ tons) to several million BTU/hr

 • Ductless Mini-Split Systems:

Capacity:

 Small Capacity:0.5 – 0.75 Ton, Medium Capacity:1 to 2 tons, Large 2.5 to 4 tons

• Hydronic Radiant Floor Heating:

Residential Applications: 10,000 BTU/hr to 40,000 BTU /hr per 1000 square feet of space. Commercial and Industrial Applications: tens of thousands to hundreds of thousands of BTU/hr.

Commercial Spaces:

Variable Refrigerant Flow (VRF) Systems/VRT:

Small-Scale Systems: 2-14 tons, Mid Scale Systems:14-56 tons, Large-Scale Systems:56-several hundred tons.

• Commercial Central Air Conditioning Systems: Small to Medium Capacity:10 to 100 tons, Medium to Large Capacity:100 to 1000 tons, Industrial Capacity: exceeding 1000 tons (3500 kW) .

 • Roof-Top Units (RTUs):

HVAC Roof Top Unit

 Small Capacity: 3 to 15 tons, Medium Capacity: {15 to 50 tons, Large Capacity: 50-150 tons & Total cooling capacities: 1 to 10 tons. Total heating capacities: 10,000 to 100,000 BTU/hr}.

• Dedicated Outdoor Air Systems (DOAS):

 Small-Scale Systems: 100-1000 CFM, Total cooling capacities: 1 to 10 tons, Total heating capacities: 10,000 to 100,000 BTU/hr, Medium-Scale Systems:{Fresh air rates: 1,000 to 5,000 CFM, Total cooling capacities: 10 to 50 tons, Total heating capacities: 100,000 to 500,000 BTU/hr}, Large-Scale Systems: {Fresh air rates: 5,000 to 50,000+ CFM, Total cooling capacities: 50 to 500+ tons, Total heating capacities: 500,000 to 5,000,000+ BTU/hr}.

• Chilled Beams:

Standard Capacity Range: 10 kW/m (3 BTU/h/ft) to60 kW/m (18 BTU/h/ft) or more.

Variable Capacity Options:

Customized Solutions:    Application-Specific Options:

How to chose the best option?

There are possibility to go trough to chose the HVAC system.

 • 1. Short term cost saving

 • 2. Long term cost saving

 • 3. Environmental priority

 • 4. Combination of above

 • Beside of those significance mentioned, there are different brands in the market

specialize in each or few categories mentioned above

Weighted Decision Matrix

Also known as a prioritization matrix or weighted scoring model, is a powerful quantitative technique used to evaluate a set of choices (such as ideas or projects) against a set of criteria.

 • In this stage as we know all different systems capabilities, then we can reject any

suggestion which is not capable to handle the load or if not fit the space. For

instance RTUs are suitable for commercial buildings as space is limited.

 • We have to ask the shareholders and parties involve the project how important is

each quality mentioned in the last page.

• Then by building a matrix with possible system and weight given to each

Example

There is a complex units of 24 condos in Vancouver, what is the best HVAC

 option if only efficiency is matters and environment?

 • This gives us only central units heat pump as only option.

 • If initial cost and efficiency both are important.

 • Each condo has average of 600SF there fore the heat load would be 600x

5~3000W / ~10000 Btu/hr => 10000*24 ~250000 Btu/hr (20 tons)

 • Cooling load~2.5*240000 ~ 600000 Btu/hr (50 tons)

Refer to above:

 • VRF, Duct less Mini Split systems and Packaged HVAC Units seem to be suitable while combined

with ERV or HRV.

 • Packaged HVAC Units: have higher cost, more noise and less efficient in Zoning comparing to other two.

 • VRFs are more efficient and provide zoning but they cant provide fresh air.

 • Minisplit units are more cost effective than VRFs in short term, but less efficient and convenient

 compared to VRFs. Also doesn’t provide fresh air.

 • Hydronic system has lower cost and more comfort but does not provide cooling.

 • The conclusion comes to VRF and use of ERV. In these case we can use one VRF for the group of 3 to 4 condos. Use of 8 tons VRF for 4 units total needed 3 VRF units.

The chat below represents the short version of the presentation

HVAC Systems In the nutshell