Monitoring it’s a key topic to understand whether a building is working properly and users behave in the correct way. In order to have some inputs about this topic a lecture from Passive House institute was presented in Darmstadt.
The main questions are: which factors we have to measure to compare calculated data with real building? How to match measured data with real data?
To know if the user behavior in correct, you have to ask directly to the users. That is what Passive House Institute did with two buildings in Darmstadt. They measured and analyzed the data of energy consumption over three years, then asked to people if they’re satisfied, 90% are satisfied and 50% are very satisfied. A minimum percentage of unsatisfied people is considered acceptable and inevitable.
When planning a monitoring there are two extreme options: minimal monitoring VS scientific monitoring. You should decide according to what is needed and which are the limitations.
It’ easier to have data on final energy side and is more difficult to have it at the useful energy level. The measurement is done on heat generation, on storage that have some losses and on distribution with losses. If the losses are few the measurement data can be used.
Minimum measurements technology required is manual reading of general meters (heat supply, thermal solar supply, power consumption, water consumption…), minimum 1 per year, best every month.
If you have a gas meter and a heat meter after the boiler you can calculate the efficiency of the boiler. You can add single meter on single flats, so you can know the system losses.
If you need a very detailed monitoring, you can have a single circuit.
In case the heat generator is a heat pump it’s important to know also the cold source temperature.
In efficient building is important to monitor electrical energy consumption, because there are more electrical consumption than heating.
Which are the influencing factors in monitoring?
- Thermal quality building
- User behavior (people, clothing, activity)
- Weather condition
- Function building services
The calculation according to the building codes algorithms are not suitable for comparison with consumption numbers, they are not accurate enough. Demand is different between consumption, to design you should make a calculation more connected with reality (e.g. Passive House Planning Package).
The deviation from law to reality (at least in Germany) is mainly in overestimation of internal gains. With PHPP they measured heating consumption very accurately, with energy losses and gains (solar gains, internal heat gains…).
In high performing buildings there are big difference due to indoor temperature. Typically internal temperature is about 21.5°C (according to past monitoring).
Ventilation can change heating demand; in passive house an air change rate from 0.2 to 0.5 can be a quite big difference (1.5 kWh/m2y).
Summing all the possible influences can up to double the consumption, in theory, but they are not present at the same time.
For hot water there is a big data fluctuation. In single house it’s difficult to predict the user behavior, in many apartment instead it can work because you can do statistics and so you can refer to average values.
At least control should be done permanently (minimum one annual date required). Deviation can be clarified by more accurate monitoring.
Rebound effect and saving potential
In passive houses the user behavior can influence the consumption very much.
In insulated building people use to have higher temperature inside; anyway in high performance houses, even if people don’t behave correctly, the extra consumption is not very high in absolute value, better than in renovated houses (not passive).
The measurement of 32 flats in Hannover (passive houses) shows that some need more heating, some need less, statistics show a typical standard deviation (1,2 kWh7m2y). The average value fits the PHPP calculation.
Measurement accuracy is not better than +/- 3 KWh/m2y.
PADIHAM AND TREVISO DREEAM PROJECT PILOT SITE MONITORING
In these projects SinCeO2, partner of DREEAM Project, use an innovative methodology to calculate energy saved.
First of all they find the key performance index of the buildings. This means facing with a big amount of data, that should be collected (276 gas bills for dwelling). Another problem is that many little actions of each tenant has an influence on the global energy consumption (e.g. number of people living in each house, hours that they spend at home, habits of use).
They installed different meters in each house and connected them with the cloud. They collected data before and after renovation.
They calculated the energy consumption with real degree days so using the real internal and external temperature. With this approach the data fits much better the real consumption than calculating it with theoretical degree days. It fits even better if data about user behavior is included.
The new consumption of each dwelling was obtained and the energy generated by solar panels was measured to determinate not only the savings derived from improvements that affect consumption, but the saving derived from self-consumption.
During the monitoring is fundamental to know all the boundary conditions, for example how many hours people stay at home. If boundary conditions change model must be adapted to understand the real energy consumption. In Treviso was done a program in DEXCELL program to know exactly how many people stay in the home.
Places for people, owner of the 109 properties in Padiham, selected 9 household to be monitored. The monitoring continued also during the works, so it could be possible to see differences as each part of the renovation was completed. They monitored internal and external temperature, humidity, kWh consumption.
The challenges of this monitoring approach were:
- Recurring connectivity issues
- Tenant engagement
- Location of site
- Staff resources
- Staff knowledge
After this monitoring period they understand that a careful costumer selection is a key starting point and is also important to work closely with contractor. Ensuring kit works correctly on site will aid tenant engagement and management of monitoring project. A good partner for communication and support it is very important.
During the meeting in Treviso 2019, Ing. Fontela from Exeleria shows the application of software and the decision support system to identify the best and cost-effective renovation scenarios for the Dreeam pilot sites.
They created a building portfolio, where buildings are pre-selected according to some archetypes. The archetypes are defined according to the building typology, age, energy performance indicator, component make-up, U-value and occupancy level or usage profile. U-values are one of the key inputs to accurately develop the energy analysis, but in most of the case they are unknown, so field measurements are needed. Also ventilation rates are often unknown, because closely linked to user behavior, so assumption must to be made in the energy calculations. Real consumption data is not available, because energy bills are private issues.
Some one site measurements have been done in the pilot sites to assess the U value, also thermographic analysis and system analysis have been done in place.
They did an inventory database for four countries across EU identifying the potential interventions and the building information. Into the Dreeam tool they implemented a building model that provides different combination of options, providing thousand of potential solutions. Then they combined also information about the preferred options by the owner and local legal requirements.
During the analysis they learn that each country provides different level of detail in terms of input data and prices can vary quite a lot in different country. Sometimes manual input and assumptions are needed for complex active solutions.
The tool was tested compared with the CARRIER tool to check the difference. Difference is less than 3%, so the accuracy is guarantee.
HSB LIVING LAB
HSB Living Lab is an experimental real building, populated by real tenants, where “everything” is measured. It’s possible to test technologies and components without risk, before to go to large scale discussion.
It’s a flexible building, and it’s modular. There is an agreement that states they can use the terrain only for 10years, so they could move it later. Being modular you can change pieces, to make experiments. Everything it’s visible, like piping, wiring, technical systems. One of the HSB Living Lab aims is to attract researchers. The whole house is filled with sensors (2000 sensors) that measures several indicators like CO2 concentration, temperature, power, etc. Researchers can ask for data or add sensors.
In the building live 40 people “full time”. Some of them are living here since the beginning of Living Lab activities in 2016. The tenants are somehow “part of the infrastructure”.
Some of the apartments have shared kitchens and showers. There are some repetitive modules so it’s possible to run A/B/C/D test with 4 different flats. In the building also lives three families with kids.
People can apply for a home in the living lab, there is a cue system to enter, so tenants are not selected.
There are 12 long-term partners for a 10years agreement.New partners can apply to do the research here, they must be coupled with one of the original 12 partners and can also ask for economical contribution.
The living lab is up and running since 2016 (built 2015). Up to now almost 80 projects, more than what they expected.
- Comfort floor heating: not done for heating, but just to have warm floor. Usually electric, so it’s difficult to do it with new rules. They are trying to make it more sustainable.
- Building integrated photovoltaic: original façade was removed to install it. They’ll next change the PV panel from black to other colours.
- USB C for smart buildings
- Fresh air closet: many times we wash clothes that are not really dirty, so different tecniques to make clothes without washing them
- Effective cleaning and recycling: sensors in the trash to tell trash company when to come to pick up the trash.
- Virtual keys
- Sustainable consumption: repair service and other
- Labtrino: reduced water consumption with intelligent meter system
- Safe home / alarm system
- Sensors to detect water leakages
- Chatbot for service and property support
- MinShed: micro plastic in laundry
- ERO app: choose the best energy source available and behave in a more energy efficient way
- WoodXZip: 12 sections in the house where you can change a whole wall part. They are testing new insulating materials at the moment
- Circul Kitchen: try to make the kitchen life span longer
- Food waste and sustainable behavioural changes
- Climate smart apartment
- Future of the laundry: sensors in the tenants clothes to see how often do they was them
- Indoor environment chemical
- Water aware
- Stormowater delay test
BUILDTOG (FIRST GENERATION) MONITORING
This first generation of Buildtog is a 4 level building with 4 apartment on each level. The aim of the project was to reduce energy consumption as much as possible, and reduce heating and cooling demand. This building reached the Passive House certification by optimizing the insulation and implementing the ventilation system with heat recovery. The remain small demand of heating is provided by district heating.
The 16 apartments have different consumption, depending also on the user behavior, but the most of them has a low energy consumption level. The consumption in practice is far under expectations.
During the monitoring from Jun 2018 to May 2019 we can see that the summer temperature was higher than the average temperature in Bremen (2 degrees more hotter), but the inside temperature was less than 26°C, a quite comfortable temperature for summer period, thanks to windows shading and ventilation. The average internal temperature was 21°C from November to April, in line with individual user requirements.
Talking about user feedbacks the most of them are satisfied or very satisfied about the comfort and the systems. A clear majority of users are satisfied with the Passive House and get along well with the technology offered.
The company produced a user manual to teach them how to use the systems in an efficient way.
Is interesting to see that people are more satisfied during summer period than in winter period, but in general we can say that the feedbacks are very positive.
You can find more information about the Buildtog and its monitoring at this link.