Energy monitoring in buidlings
The energy-efficient measures used for retrofitting of the building itself, replacement of windows, fuel switches, etc. do not often effect the practical decrease of energy demand. Research has shown that the building users’ personal behaviors and patterns keep a significant impact on the energy performance. Therefore, energy management and monitoring are a direct responses to the matter.
Energy management and monitoring provide a very detailed and accurate database with real figures for the actual energy consumption in each building. By utilization of an energy monitoring system (EMS), the real energy performance identification and energy losses estimation in the respective premises would be enabled. The EMS provides detailed and complete information needed for energy audits and at the same time it decreases the costs and terms for the implementation of the measures at higher quality and accuracy of estimations, assessments and recommendations. It allows better control of energy flows in the buildings, and adequate thermal comfort and rates for building lighting can be provided with minimum use of resources.
It is very important for the main energy consumers in the building to be determined and differentiated. For example, in the kindergarten, the main consumers are: inside light, outside light, kitchen equipment, office supply consumers (computers, PV systems, television, DVD players, etc.), special equipment (sterilizer machine), boiler, inside the heating system. In some cases, inside heating systems have to be subdivided according to the specific purpose of the building use (e.g. subdivisions: by floors, by premises, by location, east and west part, etc.). Measurement devices have to be installed on each of the identified consumers to measure electricity, gas, oil, etc. Each measurement device has to be designed on the basis of each specific case taking into account the available consumers, heating of the building, resources, etc., and to be able to send data to the main control system. All data have to be collected in the main data center. The special software analyzes the data received and if there are some deviations from the standard the software has to give a signal to the operator. Outside and inside temperature is necessary to be measured as well. All measurable data are compared with standard or statistical data. The measurement timing is at least every 15 minutes.
The benefits such EMS installations provide are the following:
in case of unnecessary energy consumption, the system detects and gives a signal to the operator. There are possibilities for the manager to regulate the system manually or for some consumers to be switched off automatically.
a very precise determination of the necessary energy efficiency measures.
measurement of the saved energy from every concrete retrofitting measure. For example, the EMS is adjusted so that the lights operate only during the night, but for some reason, during the day the lights are switched on. In this case, the system detects that, and there are two options: it will automatically switch off, or the EMS will give a signal to the operator. Or during a very hot winter day, the system detects very hot radiators, again on time the system understands that and reduces the heaters. In these cases, the advantages are related to a reaction on time, or the manager understands immediately the unnecessary consumption and stops the process. When there is sufficient statistical data it can be analyzed and opportunities for increasing the energy efficiency can be found through benchmarking. Example: we are aware of the best examples which report energy consumption of 2 kWh/sq.m for LED lighting. However, our showcase reported 3 kWh/sq.m. So, if we switch the bulbs we will report a saving of 1 kWh/sq.m. Thanks to these data we can estimate the necessary investment as profitable. In the case of implementation, we can measure real results.
But how we could make it works in the real world.?
For the building's energy monitoring a big leap forward is the use of smart and IoT devices, and the use of building automatization systems.
with those, we could manage which equipment works when it's the most energy-efficient. For example, if no one is in a room WWE could turn off the lights and air conditioning for that room with that we save energy and money. Or we could use the building as a giant t heat battery running ac full when the rooftop solar array makes the most access electricity.
To reach the final goal of using more efficiently the energy first we need a way to know how much we consume at a given time.
For this we could use ct clamps
These things clamp on to the supply and send the ac current to a database.
We need at least 3 of these they are good to work up to 150 amps if we have 3 phases which are the norm in Europe we should be able to power a 5-story building.
Now we have a stable flow of usage data but we need a way to understand that so we need software.
We could use openHab or bemserver.
We need a server to host this software we could use a DELL POWEREDGE R240 1U for that and we also need a large lan network and wireless access points for the IoT devices.
For the wireless network, we need access points all over the building good cisco, or juniper or Mikrotik, or Ubiquiti system would be sufficient.
Most smart lightswitch are terrible as a stupid switches. But that those matter now we need smart switches a would choose aqura Zigbee or Tenda wifi switches.
For heating and cooling control each office or room could get a smart thermostat and a fancoil unit .
On the roof next to the large solar array is a 4 medium heat pump chillers. Which provides the heating and cooling for the building.
We could also provide cold liquid for a server farm or something else.
For the actual energy monitoring subject we could use OpenEnergyMonitor or the building automatization software itself with a custom page which is not hard to make.
And finally, we need a way to monitor the solar for that we could use a weather API to better plan the energy usage or a solar sensor to calculate the incoming power, or a ct clamp. But a lot of solar inverters comes with a good API or app which we can connect to receive the data.
So this was my "dream" or best case-building automatization/ energy monitoring setup.