Gas scholarship supports thesis on energy efficiency

Two identical hotels side-by-side in Frankton, Queenstown provide the ideal opportunity to test the hybrid system

Lower-emission hot water systems for commercial buildings could result from a master’s thesis study comparing an all-gas system with a hybrid gas/electric alternative.

The master’s student researcher, Kez Shruthi, has been successful in winning a $5000 education grant from the Kennedy Educational Scholarship Trust to support her studies.

An employee of Rinnai NZ, Shruthi will compare two identical multi-level residential buildings in Frankton, Queenstown that are connected to a reticulated LPG network.

The water heating system in one will be modified to become a hybrid gas/electric system with electrical elements intended to reduce the on/off cycling of the gas boilers, with the other building’s system staying fully-LPG fueled.

Shruthi says the hybrid system should improve energy efficiency overall along with reducing emissions. The main use of the electrical elements will be in the off-peak period overnight when there is minimal hot water demand.

“The electrical elements will cost-effectively keep the stored hot water at the desired temperature in off-peak periods.

“With reduced need for on/off cycling of the gas heating, there will also be less stress on the system’s components which will lengthen their life,” she says.

This innovation is likely to be particularly cost-effective in the South Island where natural gas is not available and gas heating relies on higher-cost LPG.

The study is intended to last a year.

GasNZ chief executive Janet Carson says the study will demonstrate the long-term potential for gas – an essential component of New Zealand’s energy system - to transition to a lower emission fuel through clever innovation.

“While the gas infrastructure evolves to increasingly use renewable energy sources, gas is still a critical component of New Zealand’s energy mix.

“The current electricity system relies on gas to supplement renewable energy sources for electricity generation, while many commercial operations rely on gas for heating,” Carson says.

“As we transition to renewable gas, finding ways of lowering emissions and increasing efficiency through inventive tweaks to the way gas is currently used will let us keep the best of both worlds.

“New Zealand has made an extensive investment in a critical and well-used gas infrastructure that we need to preserve and continue to make effective use of, as we transition to longer-term low-carbon gas solutions such as biogas and hydrogen.”