Nadine the Cake Queen is a home business run by Nadine McCristal. She supplies bespoke cakes and desserts to the wedding industry & general public on the mid North Coast of NSW.
After completing a kitchen renovation in 2017, Nadine found that she had a problem with excess heat in the kitchen during her baking times due to an extra oven plus additional refrigeration and freezer units that had been installed. Her season begins in early September and concludes in May the following year which coincides with the hottest parts of the year.
Net Zero Carbon & Energy began by looking at the excess heat coming through the house windows, particularly two sliding doors that entered into an adjacent sunroom to the kitchen. It was monitored and it was found that these two doors alone could increase the temperatures in the kitchen, on particularly hot days, by 8-10 degrees Celsius. NZC&E worked up a plan to not only remove the heat but to also reduce her power bills & her carbon footprint, which had nearly tripled by going from $1800 to $5500+ per annum year on year.
Understanding how you use your energy
Monitoring
By monitoring six (6) points across the house which were Lighting, Hot water, Appliances, Air Conditioning and mains power, with one left to do solar when required.
This would give Nadine an understanding of how she was using power and when and what effect it has on her total energy profile.
Understanding how and when you are using energy is critical in reducing it.
Managing the Air Movement
Destratification Fan
This small wattage (22W) efficient fan is designed to balance air loads within buildings and this unit (pictured) specifically domestic homes.
This was installed to mixing cool air from the AC unit to combat the heat from the ovens. The effect was instant with a much more cooler working environment.
These fans are extremely efficient and draw only 10-22W of energy. This is less 66% less than that of a typical ceiling fan and is far more efficient in balancing the hotter air on the ceiling and cooler air on the floor.
Window Insulation
Window Insulation blinds where installed on all of the windows of the Kitchen, sunroom and adjacent Lounge. There was an immediate temperature drop in the back end part of the kitchen. In the case of two double doors on the north western part of the house, the Inflector installation resulted in an 6-8 degree reduction of heat into the kitchen. The adjacent sun room is now usable both in winter and summer.
Solar Generation & Battery
Solar Generation
6.27kW of Solar was installed with an LG Neon/Solar Edge System with 13.9 kW Tesla Powerwall 2 Battery. This was installed after the window insulation was completed. The system was installed to offset Nadine’s annual $6,500 power bill (2019). On baking days, the system covers around 90% of energy requirements and on non-baking days the system covers off 98% + of her energy needs.
Free Heating & Cooling
Solar Air Conditioner
On reviewing the first year's power bills, it was ascertained that approximately 25% of energy used was being consumed was with an 8.0kW on grid air conditioner. This was replaced by a 5.0kW Solar AC/DC Air Conditioner. This unit, as you will read on the proceeding page, offered 8 hours of free heating working in conjunction with the Inflector and the destratification fan. This unit allowed all of the daytime use to be zero cost and increased her feed in tariff on her solar by 25%.
Winter 24 Hour Test - 2019
The top graph is the energy being monitored with the colours indicating solar generation (yellow) and air conditioning (maroon) through the house monitoring system. As the sun hits the air conditioner’s solar panels, the mains power (maroon) part of the graph drops off and the solar (yellow) takes over.
The air conditioner setting was 22 degrees Celsius on the unit. The graph shows how the unit switches to solar for the air conditioner at approximately 8:30am. The monitoring then shows that the solar air conditioner switched back on again at 7:30pm at night. The unit was set in the heating mode. This means 11 hours of mains power was saved on the day due to three factors:
Solar ACDC Air Conditioner
Destratification Fan
Window Insulation
The air conditioner in conjunction with the window insulation meant that the heated air stayed in the house and wasn’t lost out of the windows and the destratification fan balance the air and keep the thermal load through the house 3 hours after the solar ran out.
Summer Testing Summer – 2021 Hybrid / AC Limiting / Solar Only
At a kilowatt hourly rate of $0.35 cents per kilowatt hour showed that the cost to run a Solar AC DC Unit in the hybrid function was approximately $0.17 cents for the first day. In AC Limiting function the cost was approximately $0.09 cents with no charge for the full solar day.
The standard Hybrid setting showed a 70% energy saving in Hybrid mode with only 30% of power required being from the grid connection. In AC Limiting mode there was a 89% reduction in energy required from the grid with only 11% required from the grid.
In full Solar Only function no power was drawn off the grid.
Results
Nadine is more than happy with the result. Along with managing the house's thermal comfort NZC & E removed the electric hot water and went to a heat pump (60% savings on hot water) and changed all of the lights to LED (66% saving on Lighting costs).
The building is significantly cooler and she has had a 71% reduction in her energy bills with her air conditioning charges reducing by 75% annually.
“I’ve always run the air conditioning with the ceiling fan, but it still didn’t mean I had the best working conditions, it was either still too cold in the lounge room or too hot it the kitchen. Once the air balancing fan went in, it made everything coordinate perfectly and meant I had one less thing to worry about, they work brilliantly. Investing in my home to create the business I wanted had an unexpected increase in my power costs. Thanks to Net Zero Carbon & Energy and their professional service, my house is much more comfortable when I work, and my energy bills are significantly lower. Moving to Amber Energy gives me peace of mind that I am helping the planet and my community."
- Nadine The Cake Queen
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