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


ABOUT ME

• 2002 BS - EECS/MSE from Berkeley• Lucky to send a chance email to Randy Katz• 2011 PhD – Economics Berkeley


GOALS

Explore collaboration, exchange information1. OFFER how I think I can help.2. GET connected to smart people

working on the same problems.


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])


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



WHY?(TOP 10 REASONS WHY THERE IS SO MUCH OPPORTUNITY)


2. Prescriptive Codes - it is hard to “prescribe” quality and performance


5. HVAC contractor training all comes from the HVAC equipment salesman or manufacturer


8. Resistance to change


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.




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?


STAKEHOLDERS / ISSUES

• Money Savings• Comfort• Contractors• Risk / Guarantees?• Effort / Convenience• Government• Monitoring?

BRAINSTORM


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.)


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


ECONOMISTS NEED ENGINEERS, ENGINEERS NEED ECONOMISTS.

BOTH NEED TO WORK TOGETHER TO INFLUENCE POLICY/POLITICIANS.

Impact

100%Engineering

100%Economics


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.


• 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


BIG DATA


GRAPHS OF ENERGY DATA


Decay curvesTemp SettingOn/Off“Away”




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.


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.


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


CONTINUING DIAGNOSTICS

• Compare (and write contracts) on as-built performance vs as designed performance• AFUE monitoring. (Check engine for a house) • Other?



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.


THANK YOUCOMMENTS APPRECIATED

[email protected]

Documents

Real time HVAC monitoring : BIG DATA SOLVES RETROFIT RISK