Real time HVAC monitoring : BIG DATA SOLVES RETROFIT RISK
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Transcript of Real time HVAC monitoring : BIG DATA SOLVES RETROFIT RISK
HOWARD CHONGA S S I S TA N T P R O F E S S O R O F E C O N O M I C S A N D
S U S TA I N A B I L I T YC O R N E L L U N I V E R S I T Y – S C H O O L O F H O T E L
A D M I N I S T R AT I O N
REAL TIME HVAC MONITORING : BIG DATA SOLVES RETROFIT
RISK
Chong – Berkeley SDB presentation - Feb 2014
Chong – Berkeley SDB presentation - Feb 2014
ABOUT ME
• 2002 BS - EECS/MSE from Berkeley• Lucky to send a chance email to Randy Katz• 2011 PhD – Economics Berkeley
Chong – Berkeley SDB presentation - Feb 2014
GOALS
Explore collaboration, exchange information1. OFFER how I think I can help.2. GET connected to smart people
working on the same problems.
Chong – Berkeley SDB presentation - Feb 2014
THE BIG QUESTION
Why are houses not being retrofitted?• Engineers suggest that this can be done.• Subsidies pay for a large portion of the work.• BUT, less than 5% of people sign up for free
retrofits.• BUT, many low income households don’t sign up
for retrofits. (<20% participation, Wolfram & Fowlie [UCB])
Chong – Berkeley SDB presentation - Feb 2014
HOUSING BRAINSTORM
In terms of cold/hot comfort• The house you grew up in• The nicest house you’ve
been in (grandparents?)• Your college apartment• The worst house you’ve
been inI live in an “renovated” 1890 house. The average American household spends $2000/yr with large variation. My propane bill this month was $740.
CALIFORNIA BUILDING CODES – THERE IS STILL LOTS OF
RETROFIT OPPORTUNITY, DESPITE “STRONG” BUILDING CODES
Chong – Berkeley SDB presentation - Feb 2014
Chong – Berkeley SDB presentation - Feb 2014
2. Prescriptive Codes - it is hard to “prescribe” quality and performance
Chong – Berkeley SDB presentation - Feb 2014
5. HVAC contractor training all comes from the HVAC equipment salesman or manufacturer
Chong – Berkeley SDB presentation - Feb 2014
BUILD QUALITY IN THE USA
• I talked to an American in the airport who told me about a bad builder. With each tract home project, he starts a new incorporated company. There are a large number of defects (that cannot be seen until many years later). • In one case, a commercial real estate lawyer
looked into filing a lawsuit. However, this builder closes each company after houses are sold. The lawyer found it “uneconomical” to sue. Though the builder has some legal liability, the culture is that there are no protections.
Chong – Berkeley SDB presentation - Feb 2014
RETROFITS
When houses aren’t performing as they should and it is economical to retrofit them, the homeowner has the right incentives to pay to fix them.
More than 70% of the homes in the US were built before 1980. Most older homes need retrofits. Some newer ones (because our build quality is bad) may also need retrofits.
Why aren’t people retrofitting their houses?
Chong – Berkeley SDB presentation - Feb 2014
STAKEHOLDERS / ISSUES
• Money Savings• Comfort• Contractors• Risk / Guarantees?• Effort / Convenience• Government• Monitoring?
BRAINSTORM
Chong – Berkeley SDB presentation - Feb 2014
THE KEY ISSUE: RISK
Current system: It takes about $200-$500 and 4 hours of time to assess one’s house. Afterwards, one is typically offered some retrofit options costing $5000-$10000 that can save up to 30% per year.
What is wrong with this? Where is the risk?
(Median US household income is about $50K.)
Chong – Berkeley SDB presentation - Feb 2014
1. There is heterogeneity in existing efficiency.2. Where are the old buildings?3. What is the observed retrofit level?
Low efficiencyHigh energy
High efficiencyLow Energy
Chong – Berkeley SDB presentation - Feb 2014
ECONOMISTS NEED ENGINEERS, ENGINEERS NEED ECONOMISTS.
BOTH NEED TO WORK TOGETHER TO INFLUENCE POLICY/POLITICIANS.
Impact
100%Engineering
100%Economics
Chong – Berkeley SDB presentation - Feb 2014
FOR IMPACT, WHAT STAKEHOLDERS NEED TO BE ENGAGED
• Stakeholders: Builders. Energy Auditors. Banks. Financing. Customers.
Engineers tend to think in terms of controllable components:• Sensors• Actuators• Control loops• Model Predictive Control• But stakeholders are the biggest “bugs” or “kinks”
in the system.
Chong – Berkeley SDB presentation - Feb 2014
• We have not solved the problem as consumers interacting with builders/retrofiters actually see it.
• The builders are in the best position to understand the risk, but they are not able to completely eliminate the risk. (non-engineers, limited budgets. Looking for the $1 solution, not the $10000 solution)
Low efficiencyHigh energy
High efficiencyLow Energy
Chong – Berkeley SDB presentation - Feb 2014
SOLVING MARKET BARRIERS TO RETROFITS
“Big Data” approaches can (1) make it easier to identify which houses need to get a costly and potentially time-wasting retrofit, (2) solve the risk component of retrofit quality. “Pay for performance” give people a guarantee, much like most other (successful) consumer experiences.
When houses aren’t performing as they should and it is economical to retrofit them, the homeowner has the right incentives to pay to fix them.
Chong – Berkeley SDB presentation - Feb 2014
ENGIN PROBLEMS
• Simple RC (time constant) characterization of thermal decay a f(constant outdoor temp)• RC characterization with varying outdoor temp.
(coupling?)• Humidity characterization with varying outdoor
temp.• Air leakage characterization from humidity profile.
Chong – Berkeley SDB presentation - Feb 2014
DATA SOLUTIONS
• Where is the temperature setpoint? What is the distribution f({24hr})• Behavior separated from the building.• RC/thermal decay daytime vs nighttime solar
gain• Thermal gains daytime vs nightime & by
location / orientation solar gain and impact of design
Chong – Berkeley SDB presentation - Feb 2014
CONTINUING DIAGNOSTICS
• Compare (and write contracts) on as-built performance vs as designed performance• AFUE monitoring. (Check engine for a house) • Other?
Chong – Berkeley SDB presentation - Feb 2014
HOW I GOT HERE
• Parents are immigrants, poor background, American Dream story.• 2002 BS Double major Engineering (EECS / Mat
Sci)• 2002-2004 “working”, included 1 day on a
garbage truck• 2011 PhD Ag and Resource Economics
I’m an Odd Animal.