Mechanical Disciplinary Research
Marissa Caldwell, Anya Godigamuwe, Valerie Miller,
Yuka Narisako, Jimmy Weaver
Variable Refrigerant Flow Systems
(VRF)
[James Weaver]
The Vapor Compression Cycle
Condenser Coil
Expansion Valve
Compressor
Evaporator Coil
Variable Refrigerant Flow/Volume Systems

A VRF System operates by sending refrigerant
between an outdoor and indoor unit.

The outdoor unit houses the condenser and
compressor.

The indoor unit houses the evaporator.

Refrigerant is varied to each indoor unit
based on the desired load using electronic
expansion valves or pulse modulating valves.

Heat Recovery is available through the reuse
of energy from superheated refrigerant.
Figure 2: VRV System in a tall building.
Provided by Daikin Industries, Ltd.
Goetzler, William. Variable Refrigerant Flow Systems. ASHRAE Journal. April 2007.
Advantages Vs. Disadvantages
Advantages:

Lightweight and modular

Flexible Design

Minimal Ductwork

Individual Comfort Control

Energy Efficient – High Part Load
Efficiency
Disadvantages:

Initial Costs

Refrigerant Piping Concerns

Cold Climate Issues

Market Acceptance

Many Require a Dedicated Outdoor Air
Figure 3: Heat Recovery VRF System. Provided by
ASHRAE Journal, April 2007.
System
Goetzler, William. Variable Refrigerant Flow Systems. ASHRAE Journal. April 2007.
Potential Project Benefits
 A multi-purpose building can
benefit from space by space
comfort control.
 Minimal Ductwork can provide
solutions to challenging space and
coordination issues.
Figure 4: Temperature distribution in a building.
Provided by Daikin Industries, Ltd.
 Energy performance from a VRF
system can improve a building
operational costs.
Figure 5: VRV system with 100% Outside Air Unit.
Provided by Daikin Industries, Ltd.
Goetzler, William. Variable Refrigerant Flow Systems. ASHRAE Journal. April 2007.
Thermal Energy Storage
[Yuka Narisako]
Thermal Energy Storage – Definition

Store unused energy when it is undesired and
release it when it is necessary to reduce energy
waste.
http://www.calmac.com/products/icebank.asp
Thermal Energy Storage – Types of Systems

Time/Consumption
based


Heating



Peak shaving
Hot water tanks in homes
Thermal mass
Cooling



Water pumped from dams
Water storage units
Ice storage units
http://www.calmac.com/products/icebank.asp
Thermal Energy Storage – Real World Example

Nissan Technical Center
North America Inc.


Farmington Hills, MI
Duquesne University


Pittsburgh, PA
Add ice making chiller and
ice storage unit
http://www.energystorageexchange.org/
Thermal Energy Storage – Possible Use for Project

Reduce cooling load by installing small chiller
and ice storage unit



Lower cost
Reduce size of mechanical room
Possibly provide cooling for future
Energy Recovery Ventilator (ERV)
[Valerie Miller]
[Energy Recovery Ventilator] – Definition



Energy Recovery Ventilators (ERV’s) utilize
conditioned waste air energy to precondition
outdoor air, by the use of a heat exchanger.
Heating and cooling
All ERV’s transfer sensible heat (temperature);
some types transfer latent heat (humidity)
Space Airconditioning PLC
Sustainable Sources
[Energy Recovery Ventilator] – Types of Systems



Thermal Wheel
Plate to Plate
Runaround Coil
Fastlane: Ventilation Equipment Limited
Live Building: Integrated Learning Centre
[Energy Recovery Ventilator] – Types of Systems

Thermal Wheel







Enthalpy Wheel
Wheel spins between
exhaust and outdoor air
duct, transferring the heat
from the hotter air to the
cooler air
Sensible and Latent heat;
transfers heat and moisture
Small cross-contamination
Ducts must be close
Plate to Plate
Runaround Coil
Fastlane: Ventilation Equipment Limited
Live Building: Integrated Learning Centre
Sacramental Municipal Utility District Energy Info. Library
Fastlane: Ventilation Equipment Limited
[Energy Recovery Ventilator] – Types of Systems


Thermal Wheel
Plate to Plate




Air streams pass through
alternating plates
Air streams never come in
contact; no crosscontamination
Ducts must be close
Fantronix Online Ventilation Solutions
Runaround Coil
Fastlane: Ventilation Equipment Limited
Fastlane: Ventilation Equipment Limited
Live Building: Integrated Learning Centre
[Energy Recovery Ventilator] – Types of Systems



Thermal Wheel
Plate to Plate
Runaround Coil



Coil’s containing a
medium run through the
exhaust system
No cross-contamination
Ducts can be any
distance
Fastlane: Ventilation Equipment Limited
Live Building: Integrated Learning Centre
Fastlane: Ventilation Equipment Limited
[Energy Recovery Ventilator] – Types of Systems
Heat Exchanger Efficiency
100
90
Efficiency (%)
80
70
60
50
Heating
40
Cooling
30
20
10
0
Thermal Wheel
Fastlane: Ventilation Equipment Limited
Live Building: Integrated Learning Centre
Trane
Plate to Plate
Runaround Coil
[Energy Recovery Ventilator] – Example

McAllister Building



(2) enthalpy wheel ERV’s
73.7% and 71.4% effective
<0.04% cross-contamination
OPP Commissioning Wikispaces
[Energy Recovery Ventilator] – Example

Carnegie Mellon University's
Intelligent Workplace



James W. Meacham’s Spring
2003 Senior Thesis



Enthalpy wheel
Reduced heating load by 77%
Grade School, Philadelphia, PA
Enthalpy Wheel cost summary
showed a cost savings of
~$25,000 in the first year, a 4
day payback period
http://www.flickr.com/photos/32215181@N08/5521845253/in/photostream/
Installing an Enthalpy Wheel in
new construction allows you to
downsize equipment and save
money up-front

Florida school saved $25,000
up-front by equipment
downsizing
Greenheck: Energy Recovery Application Manual:
Proceedings of IMEC2006: 2006 ASME International Mechanical Engineering Congress and Exposition
An FPL Technical Primer: Energy Recovery Ventilation
Greenheck: Energy Recovery Application Manual:
Earth-Coupled Systems
[Anya Godigamuwe]
Earth-Coupled Systems– Definition

Using the near
constant temperature
of the Earth to heat
spaces in winter and
to cool spaces in
summer
Introduction to Geothermal Technologies / Egg & Howard
Earth-Coupled Systems– Types of Systems
Introduction to Geothermal Technologies / Egg & Howard
Earth-Coupled Systems– Types of Systems
Introduction to Geothermal Technologies / Egg & Howard
Earth-Coupled Systems– Types of Systems
Introduction to Geothermal Technologies / Egg & Howard
Earth-Coupled Systems– Real World Example

7R Building at EEB Hub, Navy Yard, Philadelphia
Source: KieranTimberlake
Earth-Coupled Systems– Real World Example

7R Building at EEB Hub, Navy Yard, Philadelphia
Source: KieranTimberlake
Earth-Coupled Systems– Possible Use for Project
Pros


Could provide 80%
heating/cooling
needs
Short payoff period
Cons


Not suited for 24/7
cooling
Requires a large area
of land
Introduction to Geothermal Technologies / Egg & Howard
Radiant Floor Heating
Marissa Caldwell
Radiant Floor Heating – Definition




Supplies heat to the floor
from tubing or cables
under the floor
Radiant Heat Transfer
Heats from floor up
Natural circulation
through convection
http://energy.gov/energysaver/articles/radiant-heating
Hydronic vs. Electric

Hydronic




Uses pumps and valves to
regulate flow based on
design temps
Longer to heat up floor
Requires a boiler
Electric

Uses conduit to pass
electricity at night to heat
the thermal mass, and
radiate heat during the
day
Radiant Floor Heating– Types of Systems

Wet Installation



Tubing is placed within the
concrete slab
Allows for the use of energy
storage in the thermal mass
Dry Installation


Plywood is placed on top of the
tubing
It can be either sandwiched in or
the tubing is stapled to the
underside of the flooring
http://energy.gov/energysaver/articles/radiant-heating
Radiant Floor Heating – Real World Example

Herbert Jacobs House – Wisconsin


Hearst Tower – New York


Wright 1st to use radiant floor heating in a US home
Radiant floor heating was added in their three-story
atrium to avoid heating unoccupied space
California Academy of Sciences – California

35-foot-high museum space, reduced energy
through heating by 10%
http://www.calacademy.org/academy/building/sustainable_design/
Radiant Floor Heating – Possible Use for Project




This system is ideal for large spaces with high
ceilings
Improved indoor air quality
Inexpensive if the building already has a boiler
Allows for open layouts
Thermal Dynamics of Radiant Floor Heating – Darren Cent