Episode 6 – More evacuated tube solar hot water boosters

Adventures with an environment-conscious inner-urban community

2020

This was the crisis year for so many people – bushfires, COVID, job losses – and it also happened to be the year of our most adventurous emissions-reduction planning, carrying out 2 major projects a few months apart.

Stage 2 solar hot water boosters

The evacuated tube solar hot water boosters we had installed in 2018 were performing well, so it was time to build the second stage. We’d completed the design work in 2019 and had commenced the Development Application (DA) process with the City of Adelaide in September 2019. DA is required by Council if solar collectors are not mounted flat on the roof. After 9 weeks of back and forth, providing additional drawings and details, we finally received Planning Consent in mid-November.

We designed this Stage 2 set of 48 evacuated tubes to be installed at 45 degrees, optimised for winter. The 60 tubes in Stage 1 are at 30 degrees, for all-year-round performance.

Stage 2 evacuated tube solar hot water boosters - planned at 45degrees for optimised winter performance
Stage 2 evacuated tube solar hot water boosters – planned at 45degrees for optimised winter performance

By March we had checked final details and pricing with RunOnSun. When it seemed likely that State border closures due to COVID might impact delivery, we rushed through an order for the equipment. Then it was time to negotiate pricing and details with our installer, Jacks Plumbing & Gas. They’d done an excellent job installing Stage 1, so it was a no-brainer to have them back to do Stage 2.

Adding in the two additional banks of evacuated tubes went very smoothly and the system was operational on 21st May 2020.

Stage 2 evacuated tubes - installation complete
Stage 2 evacuated tubes – installation complete

Evacuated Tubes Stage 2 – installed cost

  • Gross cost = $8,196
  • less City of Adelaide subsidy $1,639
  • Nett cost = $6,557
  • emissions annual saving = 2.8tCO2-e

Lessons learnt along the way:

  • The efficient low-wattage pump installed in Stage 1 – that circulates the hot water out of the evacuated tube manifolds into the hot water storage tanks – is easily able to handle pumping for the additional 48 tubes. We now have a total of 108 tubes installed.
  • When available roof space is so limited, it is still possible to add solar collectors on some unlikely positions.
  • Starting the process for Development Approval well in advance of the planned installation schedule greatly reduced stress in managing the project.
  • It is possible to take significant load from an existing heat-pump hot water system by installing retrofit solar boosters, thereby extending the life of the heat-pumps and reducing demand on the electricity grid.

You can continue reading of our adventure with Episode 7 – Battery storage – Tesla Powerwall 2.

It’s part of our special series:
Aiming beyond NetZero at Christie Walk – Adventures with an environment-conscious inner-urban community.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s