Thermal Potential in the Built Environment
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Transcript of Thermal Potential in the Built Environment
THERMAL POTENTIAL WITHIN THE BUILT ENVIRONMENT:
Identifying locally available heat sources, heat sinks and thermal storage
Yale Carden (M.AIRAH, M.IGSHPA)GeoExchange Australia Pty Ltd
Presentation Overview Future of HVAC: Disruption or evolution?
Parallels with the energy sector
What is thermal potential?
Types of thermal potential
Case Study: Thermal potential and energy productivity
Summary
Disruption or Evolution? Thermal is energy too – and it can be renewable!
Smaller systems per sqm using local thermal potential
Energy sector: Disruption as large centralized systems and organisations
HVAC sector: Evolution as smaller, decentralised systems and organisations
Parallels with Energy Sector
Energy Sector HVAC Sector
Decreasing Demand Decreasing Demand
Local Energy Potential Local Thermal Potential
Energy Storage Thermal Storage
Decentralising Systems Centralising Systems
Matching Electrical and Thermal Energy Profiles – Energy Productivity
Parallels with Energy SectorDecreasing Demand
Decreasing Energy Demand: Higher efficiency appliances, including HVAC; Behavioural changes; On-site generation; More efficient buildings; Thin Grid Concept: grid is back-up to local (renewable) generation.
Decreasing HVAC Demand: Improved Building Design; Better Building Materials (insulation, glazing etc); Building modelling for sizing systems; Behavioural changes; Controls and temperature set points; However, offset by:
Higher design criteria for climate change; and Higher volumes of fresh air
Parallels with Energy SectorLocal Energy and Thermal Potential
Local Energy Potential: Building or Regional Scale; Solar Gain; Wind; Geothermal; Hydro; Wave / Tidal; Cogen / trigen.
Local Thermal Potential: Going beyond fossil fuels (heating) and ambient air (heating / cooling); Understanding local environment; Infrastructure (eg sewer, subways); What are the neighbours doing?
Parallels with Energy SectorEnergy Storage
Energy (electrical) Storage: Batteries; Building scale; Utility scale.
Energy (thermal) Storage: Hot / chilled water; Ice storage; Ground; Phase Change Materials.
Parallels with Energy Sector(De)Centralising Systems
Decentralising Energy Systems: Large, centralised (coal) being gradually phased out; Smaller, regional, decentralized systems in areas of high energy potential; Building specific energy systems; District scale energy systems.
Centralising HVAC Systems: Individual HVAC system per building is the norm; Increase in district heating / cooling systems; HVAC as a utility service at building or district scale.
Will we see similar scale systems in future?
Parallels with Energy SectorMatching Electrical and Thermal Energy Profiles
All electric systems;
Model hourly thermal load demand profile;
Model energy (electric) potential profile;
Identify local electrical and thermal sources;
Apply storage systems to provide gaps;
Theoretically - match thermal demand with energy potential.
What is Thermal Potential Locally available thermal energy that can be used as:
Heat source (heating) Heat sink (cooling) Thermal energy storage
Is typically constant, stable, mostly renewable;
Includes the ambient air, ground, water bodies, sewer, building foundations, infrastructure, other buildings;
Mostly excludes burning of fossil fuels;
Optimal solution is likely a hybrid approach.
Ambient Air Historically most common;
Most climate dependent;
Air sourced heat pumps;
Cooling towers (wet or dry);
Direct air exchange with heat recovery.
Ground and Water Bodies
Energy Piles
Sewer Heat Recovery Also includes wastewater / treated effluent
Not just heating – cooling also possible
20-25C heat source / sink is common
Match ‘water’ flow to heating / cooling requirements
Local projects using treated effluent: Hobart Aquatic Centre, Hobart Grand Chancellor Hotel, Hobart
District Systems
Case Study: Riverina Highlands Building
Riverina Highlands Building Energy Efficiency Project (RHBEEP) objectives: Reduce energy expenditure Reduce reliance on imported energy Reduce GHG (Green House Gas) emission Improve comfort levels in the building
What we did: GeoExchange HVAC/GSHP system installed Lighting upgrade Sub metering Ceiling insulation Solar PV
Case Study: RHBEEP Results
Building energy savings: ~80 % and $94 000 per annum
HVAC energy savings: ~71 % and $85 000 per annum
Maintenance / tenancy savings: ~$80 000 per annum
Electricity demand reduction: 75 % (Geoexchange - 49 %)
GHG Reduction: 79 tCO2
Simple Payback: ~7.6 years
Return on Investment: 11-12 %
Case Study: Thermal Energy Storage
0 2 4 6 8 10 120
5000
10000
15000
20000
25000
30000
35000
40000
Cooling (kWhrs)Heating (kWhrs)
Time (Months)
Tota
l Loa
ds (k
Whr
s)
Short term storage:Simultaneous or diurnal
Annual storage
Heat Rejection
Heat Extraction
Heat Rejection
Summary Interesting parallels between energy and HVAC Sectors;
Thermal potential is use of local resources whether natural or anthropogenic;
Thermal potential is heat sink, heat source and storage;
Ideal system balances thermal demand profile with energy potential profile
Objective is enhanced energy productivity
Thank You and Questions…
Contact DetailsName: Yale CardenCompany: GeoExchange AustraliaPhone: 02 8404 4193Email: [email protected]: www.geoexchange.com.au
