Last Updated 1 year by Lukas
In 2018, I found myself signing a contract to build a passive house (it was done by a developer, so it was standardised construction). And at the end of 2020 it was delivered. This made me happy, new passive house owner with not so small mortgage loan to pay off. In this article I’d like to share experience of living in a passive house. I’d like to tell you about the current design of the systems used and how they can be fine-tuned. In your house you may use slightly different systems, but the basic concepts would still apply.
What are the systems inside the house?
- Hybrid solar power plant (capable of island mode) with installed power of 5,4 kWp. Together with 11,5 kWh LiFePo4 battery pack and heating into water, supported by 6 kW inverter from RCT
- Recuperation (Controlled ventilation with energy recuperation) system from Atrea
- 425 l water tank system with flow-through water heating. Also works as internal heat-pump unit
- Outside heat-pump unit Sinclair ASGE-12BI with 3,5 kW cooling and 4 kW heating power
- Loxon smart home + PLC and SSR relays (aka Watt router) to control water heating from solar system
- 65 l water heater to offer on-demand hot water
- E-vodnik water monitoring system (with flooding prevention)
- Katex water softener system with water filtration
- Jablotron security system
- Outside, automatic window curtains
How are these systems interconnected?
Purpose of the solar power system is to cover the electricity needs of the house. When the system produces more electricity than is needed, it’s stored in a 11.5kWh battery (90% usable capacity). When the battery is charged up to 70%, the system also switches on the 3-phase water heater (up to 6kW in total, 2kW per phase). Behaviour of the whole system is controlled by a PLC which measures power consumption and power distribution. The PLC controls how much power is transferred to the water via SSR relays based on actual solar production. Battery charging is controlled by the RCT inverter itself (it is proprietary technology. Inverter and battery are from the same manufacturer). Each time the priority is 1) consumption of the house, 2) charging of the battery, 3) transfer of power to water (heating), 4) export to the external grid.
Storage in water is ensured by internal water tank with 425 l of technical water (you don’t use this water directly, it’s just energy storage). The technical water is used to heat the water flowing from the outside and it’s directly used as a heating medium for the air heating system of the house through the recuperation unit. The water tank, the recuperation unit and the external heat pump unit are all supplied by Atrea. The whole system ensures these purposes: Air heating, air cooling (AC), storage of extra energy from the sun, effective ventilation of the house (recuperation of waste air energy). Purpose of the external heat pump unit is to heat water and in summer to lower the temperature inside the house. In case the performance of the heat pump is not sufficient. The system has a bivalent source of thermal energy, which is a 3-phase, 6kW heating rod inside the water tank.
The Loxon smart home is integrating these systems. And providing the user with a single interface to make changes. It also has several comfort features such as automatic control of curtains, lights, setting schedules for temperature, interconnection with motion sensors to set the most propriete internal climate in the house. The Jablotron security system is connected to the security agency and works independently of other home systems. It’s main purpose is to secure the house and notify you in case of any problems.
The additional 65-litre water heater is used to provide instant hot water and do not want to heat up the entire 425-litre water tank. It also allows you to change the setup of the system and make it more efficient. E-vodnik measures water consumption and can close the main water valve remotely. It’s even able to learn expected water consumption and, based on intelligent heuristics, detect potential water leaks (and potentially close water valve in response). A Katex water softener combined with a flow-through water filter (50 microns) ensures that limescale and solid particles are prevented from entering the home’s internal water system. This prolongs the life of appliances and internal valves.