SUSTAINABLE HOUSE DAY - BACKGROUND, EXPLANATIONS, MATERIAL to help answer QUESTIONS

Red entries refer to the house profile items on the SHD website.

Name: Broker’s View

Top left - Front of house, escarpment in background; Top right - escarpment view (Brokers peak) from westerly window; Bottom left - same view in telephoto; Bottom right - Reverse telephoto view of house from Brokers peak

The original plan, for a new Ichijo home (prefabricated overseas) offering up to 8.4 stars NatHERS, was abandoned for a more sustainable approach – upgrading an existing 2-storey architect-designed home in a location with a more coastal climate.We had planned to buy a block of land or a knockdown rebuild in Sydney and put up a fully insulated and sealed house that would have needed heating/cooling, if at all, only for a short period early morning and/or evening and would have given a constant ~22C irrespective of outside extremes. However, difficulties with the Sydney housing market and a desire to avoid the more inland climates, for which Ichijo and similar houses were well suited, altered this plan. We ended up with an attractive property ~3km from the sea, where the seasonal and daily temperature ranges were moderate. It was feasible to greatly enhance the existing passive design and add many energy efficiency and other active features. The aim was to be energy positive and have zero emissions, without going to extremes of sealing and insulation.

Photos showing near-coast location: Left - sea view (~3km) from easterly window Right - same view in telephoto

Passive design – decks with eaves on all sides, cathedral ceilings and reflective roof paint – was complemented with clerestory window films, double-glazed skylight, numerous blinds (honeycomb and reflective type), awnings and curtains, all actively-managed with respect to outside temperature and sun orientation.The house, facing slightly east of north, had covered decks on all sides which could transmit low-orientation sun while shading high-orientation sun from the downstairs living areas. These areas had numerous windows giving excellent garden, bush and escarpment views while being shielded from neighbours. Therefore reflective roller blinds were chosen

to maintain this visual outlook while reducing glare, ultraviolet and infrared (heat).

One of the 12 reflective blinds in the halfway position to show comparative outlooks

UV rejection >99%; Glare reduction 92%; Energy rejection 49%

Bronze/Bronze selected: “Enhances garden/bushland views and goes well with timber window frames”

The upstairs bedroom, bathroom and office areas had no external shading and were less private. Honeycomb blinds were appropriate and were used on all upstairs windows and on downstairs windows facing the street. Some of these blinds could be opened top down or bottom up to provide selective shading and views.

Photos show effect of honeycomb blinds - good protection from UV, Glare and Heat, with some light transmission but unlike reflective blinds views are cut off

The remaining, high clerestory windows of unusual shape (example in photos above) were coated with metallic films, similar to the reflective blinds. These films gave 99% UV , 82% glare, 70% heat rejection and of course are fixed in position.

Although all blinds represent “passive” design, they were actively managed, together with the windows themselves, for best outcomes according to time of day and seasonal changes. Basically, closed when one wants to keep the sun and/or external hot/cold air out of the house, and open when one wants to let sun and/or external hot/cold air into the house. The numerous blinds were complemented by a few outside awnings (photo, left) for supplementary shading; and by inside curtains (photo, right) for flexibility or for closing off unused areas to help focus air conditioning needs. Lockable security doors and windows could be left open, overnight if necessary, for maximum cross-ventilation whenever required.

Active aspects: *ceiling and roof insulation (walls, underfloor, enhanced weather sealing to be done next) *whirlybird, solar and ceiling fan ventilation*reverse cycle a/c’s arranged for downstairs heating to also reach upstairs and upstairs cooling to also flow downstairsIn a 2-storey house warm air rises and cold air falls, allowing the several reverse cycle air conditioners to also be actively managed. For example winter heating in the downstairs living area in the evening flows up to the bedroom(s), while daytime summer cooling in the

upstairs offices flows down to the kitchen and living areas to help provide evening comfort.

A Velux double-glazed electrically-operated skylight was installed (replacing a translucent plastic sheet) to minimise heat build up (or cold air entry) at the highest part of the house.

The mix of cathedral and flat ceilings and complex attic space was insulated with Bradford Gold Glasswool Batts (R3.5 and 4.1) to the pitched ceiling and R2.0 batts to the raked walls in the ceiling space.

The colorbond roof required repainting and special reflective paint of the same green colour was used. There have been misleading claims about the effectiveness of such paints, especially as lighter coloured ordinary paints are at least as good (in fact white is best but is almost never allowed/used). Our independent contractors expected a small but worthwhile difference, which we have since observed.

Contractors spraying reflective paint on the less accessible parts of the roof

The overall effect of these passive and active features was to delay any need for cooling upstairs even on hot (30C+) days until mid to late afternoon. The heat stored in the attic and roof insulation, potentially released at night into bedrooms, was partially removed via whirlybirds, solar ventilator and ceiling fans. These vents were closed in winter to minimise heat losses.

The insulation aspect of the house is incomplete, notably on the extensive east and west-facing brick walls that are hot in summer and cold in winter. Also while draught-proofing has been improved, it is inadequate particularly on the regular windy days. Therefore cavity wall insulation and professional weather sealing are to be explored next.

Active aspects:*solar panels ac and dc coupled to two battery storage systems, the first in 2015 A first set of solar panels 12 x 245W split into two lots of six panels in northerly and westerly orientations, was installed in 2013. German Aleo panels were used partly because battery storage was being offered as an add-on future option. However the local installer went out of business before this came about, probably due to the drop in new installations caused by winding back of the NSW feed-in tariff. Later on, AGL Energy, a new subsidiary of AGL, was planning for the future and became a pioneer of household lithium battery storage in 2015 using PowerLegato LiFePO4 battery modules. We were one of the first in Australia to take up their subsidised offer in November 2015. After the initial testing and troubleshooting, this system has operated well for nearly two years now.

It has a capacity of 7.2kWh with 80% depth of discharge so that 6kWh is useable. (This would be far more than the equivalent lead-acid battery which is also much heavier.) There is a maximum power output of 3kW at 240V, selectable modes of operation including backup power during blackouts, and a multi-year, thousands of cycles guarantee. AGL has since offered larger capacity batteries from other manufacturers.

As part of the AGL retrofit process, six panels were relocated so that all were on one string, since the second string was needed for the operation of the battery system. Also the existing Growatt inverter was made redundant by the grid-interactive inverter integrated with the battery module. With 12 panels now oriented in the same westerly direction (photo below left) spanning 2 rows of three panels + 3 rows of two panels, partial shading issues arose mainly from mid-afternoon to sunset. (Even if only one panel is partly shaded, the

series nature of string systems means the output of all panels is reduced). Therefore Tigo optimisers (photo below right) were retrofitted to pairs of panels so that individual panel outputs were maintained and added together. The overall system has generated over 9MWh in 21 months (6m before and 15m after the panel optimisers) since the AGL battery was installed.

The relocation of the six more northerly facing panels vacated space for additional panels; 7 x 260W were installed in April 2016 (photo below left), this time incorporating individual micro-inverters (Enphase, photo below right). These directly provide 240V ac and also aggregate the individual panel outputs thus overcoming shading issues. It was not possible (and not intended) to link this output to the AGL battery, which was dc-coupled. Rather this was a step towards a second, ac-coupled, battery system, taking into account the rapid development and update foreshadowed by the termination of the 60c/kWh NSW feed-in tariff in December 2016.

Both sets of solar panels, the Tigo optimisers and the AGL battery are all monitored via the internet and displays (photos below). These were excellent for monthly data collection and performance analysis, in conjunction with the meter box readings of solar exports and grid consumption. Also for trouble shooting but this was rarely needed.

*heat pump hot water via PV *CO2 refrigerantAs part of the plan to make use of the new solar output (and go off gas), a Sanden heat pump hot water system was installed to replace our 8 year old gas hot water system, also in April 2016. This heat pump was 1.0kW and high efficiency (COP ~4.5) such that it provided 4.5kW thermal. It required only up to an hour or two each day, timed to coincide with the peak solar output of up to ~1.5kW, to maintain 315 litres of hot water. It also featured CO2 as the heat transfer medium (refrigerant R744). This means a greenhouse neutral lifecycle. Conventional refrigerants are now ozone-friendly but very greenhouse-intensive!

Because the heat pump used only 1-2kWh/day of PV input, the output from the second set of solar panels was mainly exported, together with any smaller excess from the AGL system, for a minimal return (up to June 2016) of ~5c/kWh. A 240V external power point was therefore installed parallel with the heat pump so that some of that excess solar could be used to power appliances directly and/or to charge 24V, 36V and 48V LiFePO4 batteries. These in turn were used directly to power electric bikes and indirectly to run 240V appliances via a stand-alone inverter, pending a more permanent and automated second battery system.

*solar panels ac and dc coupled to TWO battery storage systems, the first in 2015The second battery storage system, together with additional solar panels fitted with microinverters, was ordered in December 2016 through the community bulkbuy organisation Suncrowd. The Tesla Powerwall 2 was chosen at 13.5kWh, double the capacity of the preceding Powerwall 1 model, yet was the same price.

An independent analysis (chart below) of numerous battery systems showed the Tesla to be the most cost-effective. Still not necessarily an economic return proposition relative to investing in a term deposit. The Tesla has effectively halved in price per kWh in about a year, demonstrating how battery costs will continue to fall. So real returns on investment can be expected in the near future.

Despite delivery and other delays largely due to Tesla, it is expected at the time of writing that the system will be installed before SHD. The maximum continuous power output is 5kW and 10-year guarantees, similar to the AGL system. The electrical loads are to be balanced between the two systems. The combined system will provide grid-independence except during successive days without much sun.

*induction cooktop *gas account closedTo maximise utilisation of the combined solar output and combined battery storage, we replaced our gas cooktop with an electric induction cooktop (photo).

Then closed our gas account.

It is difficult to estimate savings arising from going off gas, or indeed from any of the individual measures like blinds, insulation, efficient appliances, solar panels, batteries etc because of the continuous and overlapping nature of the changes made on both the supply and demand sides. However, the average total household demand across the last winter

season was ~25kWh/day, with the largest component being air conditioner heating needs in the early morning and evening. That demand would have been much higher without the blinds, insulation, lighting etc measures. If that 25kWh/day had been supplied entirely from the grid at 30c/kWh over ~90 days, that would equate to $675 plus the connection charge. That cost will be avoided from the solar and battery input most of the time. Excess solar exported will more than compensate for the unavoidable grid imports during long periods of cloudy weather and will be especially significant during long sunny periods. At the minimum11-12c/kWh feed-in tariff applying from July 2017, there should be zero net electricity costs and probably enough to cover the daily connection charge as well. This is the basis for the conservative savings of $800 per quarter entered on the SHD website.

*near 100% LED lighting – downlights, screw/bayonet, floods, strips. We replaced nearly all halogen, incandescent and fluorescent lights with LEDs. As a result we have LED downlights, strip lights, floodlights and bayonet/screw globes (photos below). The total wattage is about 20% of the former situation. We also upgraded some older electric appliances to energy-efficient models.

*electric bikes front, central and rear drive *electric car on order, charging from PV *battery banks with BMS for e-bikes, RV’s or solar microinverter inputWe have several electric bikes and build our own battery banks from individual cylindrical and prismatic LiFePO4 cells to drive 24V, 36V and 48V motors. These motors are located on the front wheel, central drive and rear wheel on different bikes. The central drive is most efficient.

�Photos L to R show our e-bikes with front wheel, drive chain and rear wheel motors

Home made battery banks were and probably still are superior to most supplied with e-bikes, giving greater range before recharging, which is from the solar output. Unlike 240V systems, it is legal for anyone to work up to a nominal 50V.But it does require some knowledge and experience as even the very safe and widely used type of lithium battery (LiFePO4) requires a battery management system (BMS). Along specific chargers that prevent charging over specified maxima and discharging below specified minima.

Photos left: home made 16 cell (48V nominal 15Ah) LiFePO4 battery bank; right: LiFePO4 batteries are much lighter and better performance than conventional lead-acid batteries. One can replace the manufacturers battery in e-bikes and in RV’s like our off-road camper trailer, allowing several days away from grid power

An electric car (Tesla or other make) is planned for 2018 with charging from solar and overnight top-up from the batteries, thus maximising the use and value of the combined systems.

The gardens are mostly native plants/trees and edibles. Watering via 3×5000 litre tanks, along with various compost heaps and a worm farm.Considerable effort was expended to remove weeds, exotics, tree stumps etc from the gardens and lawns, to revitalise the soil, provide new garden beds, compost bins, worm farm etc. Drainage, termite protection and underfloor ventilation were all improved.

Revitalised garden

Rainwater tanks were installed at the rear of the garden while protecting Illawarra flame trees located there. These tanks connected via a long trench under the lawn to the underfloor of the house and up to three downpipes. Gravity flow fills the tanks and a pump provides good pressure to three taps, including one at the front garden a long way from the tanks. This was a much better approach, based on expert advice, than smaller tanks or bladder tanks under the house and elsewhere. The trench works are soon invisible and the tanks themselves will be screened by native shrubs growing in the raised garden bed in front.

The adjacent bushland and creek were cleared of extensive weeds and regenerated with advice from Council Bushcare.This effort extended to the bushland and creek area adjacent to the back fence and

accessible from the gate there. Although it belongs to Council or National Parks, who do not have the resources to maintain everything, we felt a responsibility to rehabilitate and look after the area next to and beyond our boundaries. Weeds, exotics, dead trees, fallen branches etc were removed; the stream bed cleared upstream and downstream; paths and steps (photo)(re)constructed; soil processed, fertilised and terraced; an old chicken coup repaired and used for a compost heap and storage. Council Bushcare advised on, and provided from the Botanic Gardens, suitable plants and shrubs to help stabilise the stream banks.

Recycling of logs, branches, bricks, pavers, metal and wood.

Logs and branches were recycled for garden borders, pathways etc (photos top and bottom left). Many more were used along with other “green litter” to protect the stream banks, both from erosion by floodwaters and to limit the spread of weeds. Council Bushcare had suggested this, while unusable and weeds went to the Council Green Waste Facility. Excess pavers and bricks left under the house were also reused for borders, paths and raised garden beds (photo top right). Wood also left behind replaced rotted fence posts. A long aluminium drain cover from the scrapyard made an excellent bridge over the stream (photo bottom left). A bee “hotel” was made by drilling holes in suitable logs and placing these in a recycled letterbox (photo bottom right).

Waxwood, available locally, was used instead of toxic treated pine for terracing the front garden down from street level - photo below.

Now a haven for birds, frogs, other species.

The end result is an attractive and shady rainforest area that attracts birds, frogs and other species (photos above). We have contributed to a “citizen scientist” study by academics of the bird species by photographing and identifying the numerous visitors. The creek can now flow freely and more directly in times of rain (photo below), at least to the next downstream area!