California Energy Commission Funded Research Project Energy Research on Improving the Balancing and Mixing of Domestic Hot Water California Energy Commission Funded Research Project

About Enovative Los Angeles based water and energy efficiency company Product development and manufacturing in the field of hot water control systems Independent and government funded research Water and energy retrofit services

CDHW Energy Flow Graph courtesy of California Utilities Statewide Codes and Standards Team, “Multifamily Central DHW and Solar Water Heating”, Oct. 2011

Research Focus Unbalanced Recirculation Loops- The problem of recirculation loops not having proper balancing valves to equalize water flow rates and temperatures throughout the network of pipes. Fixture Crossover- The problem associated with faulty faucet and shower fixtures, which allows cold water to infiltrate the hot water piping

What is unbalanced Circulation?

What is Crossover? When faulty mixing valves cause uncontrolled mixing between the hot and cold water pipes Can potentially happen at any point where hot and cold water pipes meet May be asymptomatic

What is Crossover? Without Crossover With Crossover

Mixing Valve and Cartridge Crossover due to failed mixing cartridges: Other causes of crossover may include: mop sinks, washing machine connections,

Symptoms of Crossover Fluctuating and unsteady water temperatures Long hot water wait times Lukewarm water temperatures, never hot Different hot water temperatures at different fixtures in the dwelling unit No hot water Hot water in the toilet No symptoms, water is an acceptable temperature

Other Sources of Crossover Kitchen spray nozzles Mop sinks Laundry machines Any fixture that keeps the hot and cold in an “open” circuit

Research Goals Identify the frequency of crossover issue Develop method to test and identify it Evaluate ideal fix to reduce or eliminate issue Savings potential How to detect Crossover? How wide spread is the issue? How much energy is wasted? Potential for energy and financial saving?

Experimental Setup at Lab Facility

Temperature Differential Method The Tests Method Scenario 1 Result Scenario 2 Result Verification Notes Pressure Gauge Method Detected Not Detected Method Validated Quickest, building-level test Water Flow Method Building-level and pinpointing detection possible Eatherton Method Pinpointing detection possible, non-invasive Temperature Differential Method N/A Invalid Can be indicative of crossover Pump Control Method Discarded, but may reveal crossover symptoms Water Meter Method Only possible in some buildings

How To Test For Crossover Pressure Gauge Method Eatherton Method System for detecting crossover within a building Will not pinpoint exact location of crossover, only discover if happening somewhere in the building Can be quickly and easily performed on any building System for detecting crossover at the fixture point Helps determine if a particular mixing valve is failing and needs fixing Can be easy or difficult to conduct, depending on how the fixture is set up

Pressure Gauge Method

Accessing the Mixing Valve

Conducting the Eatherton Method

Initial Results Out of 100 buildings tested so far, about half have tested positive for crossover in the building Level of severity has ranged from mild to severe Potential for energy savings may be substantial

Crossover Case Study Largest multifamily building in San Diego 40 stories (2) large boiler systems feeding (6) loops with electric re-heat tanks Each loop services roughly 100 units

Crossover Case Study- San Diego Pressure Regulating Valves for the hot and cold water piping for one of the loops

Project Next Steps Baseline data collection Tracking 10 building with existing crossover issues, ranging from 10-60 units. Monitoring temperatures, run times and pressure Repair crossover After 2-3 months baseline data collection, replace all faulty mixing valves or install check valves to eliminate all crossover flow in the building Post-fix data collection Post-fix data collection and calculate any resulting efficiency gains

Dwelling Units = Spring loaded check valve HW Supply HW Return Pump City Gardens Apartments Total # of Units = 23 Number of Stories = 2

Preliminary Findings First test sited demonstrated approximately 18% reduction in water heater energy use Tenants informed us water was much hotter and consistent than prior to the fix Would suggest that is now possible to lower tank temperature as temperatures are more steady Additional savings to be had from implementing recirculation pump controls

Project Future Tasks Task 5 – Recommendations for codes & standards update (August, 2016) Task 6 – Technology Transfer (December, 2016) End of Project (June, 2017)

Gabriel Ayala Enovative gabe@enovativegroup.com Thank You Gabriel Ayala Enovative gabe@enovativegroup.com