ADVANCED TECHNOLOGIES FOR AIR-CONDITIONING · FOR AIR-CONDITIONING William P. Bahnfleth , PhD, PE,...

ADVANCED TECHNOLOGIES FOR AIR-CONDITIONING

William P. Bahnfleth, PhD, PE, FASHRAE, FASME, FISIAQProfessor of Architectural Engineering, Director Indoor Environment Center

The Pennsylvania State University, USA

Outline

■ What is “advanced” technology?

■ Advanced HVAC technologies

– Indoor air quality and comfort

– Energy efficiency

– Grid Management/demand response

– Environmental protection

– Quality maintenance

■ Summary

17 Nov 2016 EMSD Summit - Imaginovate HK 2

WHAT IS “ADVANCED” TECHNOLOGY?


“Advanced”

■ Highly developed

■ Better meets existing need

■ Makes new capabilities practical

■ May be

– Component

– System

– Process

■ New application of existing technology


INDOOR AIR QUALITY AND COMFORT


IAQ Issues

■ Current standard is mainly perceived air quality

■ Research suggests minimum standards fall short of achievable health and productivity outcomes

■ Concern about epidemic, drug-resistant airborne infections


IAQ Issues

■ Current control approaches emphasize ventilation + moderate particulate filtration

■ Outdoor air quality is poor in many countries and urban areas

■ Even if outside air is high quality, conditioning it is expensive

■ WHO - ~7M excess deaths per year due to PM2.5 exposure


Advanced Technology for IAQ –Particulate Filtration

Montgomery, et al. 2015. Financial implications of modifications to building filtration systems. Building and Environment 85:17-28.


Where outdoor PM is a concern, increase filter efficiency – ASHRAE Standard 62.1 has moved from MERV 6 to MERV 8 minimum…MERV 11 - 13 is much better

MERV Grade Efficiency Curves

■ Health effects concerns increase at and below 2.5m

■ Efficiency changes from ~ 20% for 1 m at MERV 6 (old ASHRAE 62.1 min) to 30% for MERV 8 (62.1-2013) to 50% for MERV 11

■ Most-penetrating particle efficiency changes from ~5% for MERV 6 to 15% for MERV 11 and ~40% for MERV 13


Advanced Technology for IAQ – Air Cleaners for Gas and Microbial Contaminants

■ Combine ventilation with air treatment for gas phase and microbial contaminants

■ Reduce ventilation requirements or meet higher performance goals

■ Demonstrated technologies– Sorption media– Ultraviolet germicidal irradiation

■ Newer packaged air cleaners incorporate multiple air treatment modes


Thermal Comfort Issues

■ Thermal comfort, health and productivity are linked

■ Best combinations of parameters for minimum energy use

– Temperature

– Humidity

– Radiant temperature

– Air movement

…and ~12% increase in SBS symptoms per 1ºC above 22.5ºC

Source: Seppänen, O. and W. Fisk. 2006. Some Quantitative Relations between Indoor Environmental Quality and Work Performance or Health. HVAC&R Research.


Thermal Comfort Issues

Shifting views of comfort and what is acceptable – partially driven by energy considerations


Static, PMV-based method and adaptive method for full natural ventilation from ASHRAE Standard 55-2013

Advanced Technology for Comfort

■ Dedicated Outdoor Air Systems– Separate sensible and latent

cooling– Guarantee ventilation supply– Integrated total energy recovery– Compatible with efficient

sensible space conditioning systems■ Radiant■ Chilled beam■ Heat pump■ VRF■ VAV with economizer


ENERGY EFFICIENCY


Energy Efficiency Issues

■ Constrained by IAQ and comfort – what is definition of acceptability?

■ Component efficiency does not guarantee system efficiency

■ Water use of systems has become a concern

■ Motivation for efficiency has multiple drivers

– Resource conservation – energy independence/preserve status quo

– Environmental protection – tied to use of fossil fuels

– Large scale renewable energy supply is disruptive – requires new grid management approach


Advanced Technologies for Energy Efficiency – Some Examples■ DOAS systems (previously discussed)

■ Ground coupled heat pumps

■ Solar driven absorption cooling

■ Liquid desiccant cooling and dehumidification

■ Advanced air-air energy recovery

… and Controls


Advanced Technology for Energy Efficiency – Ground Coupled Heat Pumps

■ Balanced heating and cooling is best for economics but can be predominantly heating or cooling

■ Heating source/cooling sink temperatures more favorable, increase COP

■ When heating and cooling occur simultaneously, loop systems can exchange heat between HPs, further improving COP


Advanced Technology for Energy Efficiency – Desiccant Cooling■ Direct use of liquid desiccants to

handle latent load

■ Hybrid with compressor-based cooling that allows higher evaporating temperature

■ Compatible with waste heat regeneration

– Exhaust air

– Process


Advanced Technology for Energy Efficiency – Solar Absorption


Familiar base technology, new combinations for widespread application –expands concept of waste heat-based cooling to solar thermal and PV

Advanced Technology for Energy Efficiency – Energy Recovery Devices■ Desiccant wheels

■ Heat pipes

■ Moisture-permeable membranes

■ Desiccant coated coils


GRID AND DEMAND RESPONSE


Demand Response/Electric Grid Issues

■ Demand side issues

– Much of peak demand is due to air-conditioning load in the summer

– Major benefits from technologies that flatten the peak

■ Supply side issues

– Electric grid can absorb small amounts of power input from solar, wind, and other highly variable source without affecting conventional production

– Large, rapid fluctuations in renewable supply are difficult to manage

– Great need for storage technologies that help manage the grid as renewable supply increases


The “Duck Curve” – Evening Electric Demand Peak after Peak Cooling Hours


http://www.caiso.com/outlook/SystemStatus.html

Renewable Production, MW Generation Required, MW

Advanced Technologies for Demand Response – Cool Thermal Storage■ Cool thermal energy storage

– Well developed technology

– Underutilized

– Previously used primarily for load shifting to reduce utility costs and as emergency capacity

– New application for responding to rapid grid demand shifts


Advanced Technologies for Demand Response – Cool Thermal Storage

■ TES converts electricity to cooling capacity for later use at lower cost thanbatteries

■ $100/kWh widely cited barrier for cost-effective electric storage

■ $100/kWh TES is feasible today– Chilled water– US$80/ton-hour, ~US $2/gal– 0.8 kW/ton (water cooled)– Lower costs possible for larger

systems

6/9/2016 PG&E PLS-TES Program 25

Rocky Mountain Institute 2014 – The Economics of Grid Defection

Advanced Technologies – Demand Response and Grid■ District energy

– Cooling, heating, power production, alone or combined

– Aggregates loads into flatter profiles– Peak load much lower than connected

load– Most cost-effective application of

thermal storage– Saves mechanical space in buildings– More efficient equipment, better

maintenance than distributed systems– Higher reliability for users– Supports multiple conventional and

renewable energy sources– Supports deep water cooling and heat

rejection


ENVIRONMENTAL PROTECTION


Advanced Technologies –Environmental Protection■ Briefly…

– Any technology that reduces conventional energy resource use, especially fossil fuels

– Any technology that reduces the water use of systems

– Any technology that facilitates greater use of renewable energy

– Next generation refrigerants with zero ODP, near-zero GWP

■ With focus on renewable electric generation, transition toward more use of electricity seems likely


QUALITY MAINTENANCE


Quality Maintenance Issues

■ Any system that is not maintained or operated properly can be a “bad” system

■ Well-demonstrated that at least 15% of energy used for HVAC is wasted due to sub-par performance

■ Degradation of performance is ongoing and must be countered by effective performance assessment and corrective measures


Advanced Technologies – Quality Maintenance■ Internet of Things/Big Data

– Merging of equipment and controls

– Extract data to cloud

– Optimize performance considering system data, weather data, utility data, etc.

– Diagnose faults

– IEQ monitoring

■ Ongoing commissioning and other post-occupancy evaluation and rating processes

■ Energy disclosure policies


Disclosure Laws in the US


CONCLUSIONS


Conclusions

■ Sometimes the best new technology is old technology reimagined – advanced thinking

■ Advanced technology can be hardware, software, process

■ Indoor environmental quality is the place to start

■ Energy saving technology today emphasizes efficiency, energy recovery, renewable energy compatibility

■ Buildings in the future will need to help manage the grid more effectively – the technology is there or developing

■ Monitoring and maintenance is essential to benefitting from advanced technology


THANK YOU!William P. [email protected]

By Ryan Cheng - http://www.flickr.com/photos/ehoba/4815747358/, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=13990559

ADVANCED TECHNOLOGIES FOR AIR-CONDITIONING · FOR AIR-CONDITIONING William P. Bahnfleth , PhD, PE,...

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