The challenge of ensuring comfort and indoor air quality at the lowest energy cost
Table of Contents
Offices, schools, public buildings, manufacturing plants… guaranteeing the well-being and the comfort of occupants at the lowest energy costs is the objective of TEM (Engie Solutions).
The temperature felt, and the air breathed, can have a direct influence on the behaviour of occupants and employees.
Poor air quality can cause health and productivity problems among employees (fatigue, sleepiness, drop in concentration, sick-leaves, etc.).
Business performance is therefore directly impacted by this.
What is more, discomfort is often linked to energy overconsumption.
Quality score campaigns to measure indoor air quality and comfort
TEM and Energis have collaborated for several years in projects aimed at optimising indoor air quality & comfort in office buildings and industrial sites.
This is even more the case since the recent federal law in Belgium, which regulates the levels of CO2 in confined spaces. In fact, the law requires that the employer take the necessary technical and/or organisational measures to ensure that the CO2 concentration in the work space is less than 900 ppm.
TEM is a branch of Engie Solutions that specializes in technical maintenance of buildings and industry. TEM takes care of about 370 buildings and 265 heating plants in Belgium.
In order to perform quality score campaigns to measure indoor air quality and comfort, TEM combines the use of Enless Wireless radio sensors and the Energis.Cloud platform to analyse if the thresholds (based on the legal conditions) relative to temperature, humidity and CO2 are properly met. Depending on the situation, the campaigns can last from one week to several years.
The values of temperature, relative humidity and CO2 are read generally every 15 minutes via Enless Wireless Sigfox ambient transmitters. The setting of the periodicity is done during the installation of the transmitters, via the Sigfox Backend, and can then be modified simply and remotely at any time.
The data collected by the Enless probes and transmitted via the Sigfox cloud is then monitored and visualised on the Energis.Cloud software.
Improved reactivity of technical teams
The Energis.Cloud software notifies the technical teams when a threshold is about to be exceeded (for example, legal thresholds for CO2 or temperature). If alarming values are detected, the teams take corrective actions directly (modification of operating hours, replacement of defective equipment, etc.).
The audits conducted also indicate if the installations in place (heating, air conditioning, ventilation systems, etc.) function correctly and are optimally configured.
FOUR USE CASES
1. Short-term humidity audit
This campaign was conducted in a tower building, there was a humidity issue. Before deciding how to intervene, an audit was conducted, installing 22 Enless sensors in the basement. The data collected was then analysed on Energis.Cloud and allowed TEM to know exactly which investments to make without overinvesting. In this case 8 dehumidifiers needed to be installed to solve the problem.
2. Comfort campaign
This campaign was conducted in a courthouse during over a year. There, the audit conducted put in light two main problems: energy overconsumption and discomfort.
TEM measured temperatures using the Enless sensors and monitored the data over several months and seasons. The monitoring showed discomfort and overconsumption throughout the year.
During the summer, temperatures were most of the time above the threshold, which generated complaints from occupants.
In fact, the comfort score during occupancy hours was not satisfactory as half of the time temperature was not within the thresholds.
On the other hand, during winter time, indoor temperatures were then compared to external temperatures, which showed that there were 24° during night time inside the building while there were 10° outside.
Needless to say, energy wastes were significant. Regulating the heating system based on calendars and occupation hours, allowed to generate direct energy savings without investing in new equipment.
3. Long-term humidity campaign in a printing house to protect stocked raw material
TEM conducted this campaign to ensure that the paper stocked is protected against excessive humidity.
In this case, the campaign is a long-term one, where TEM ensures long-term maintenance. The site was equipped with radio transmitters for ambient temperature and humidity. The data collected is monitored in real time on Energis.Cloud and alarms allow avoiding transpassing the quality thresholds.
4. Indoor air quality and energy efficiency campaign
In an aerospace plant, TEM carried out another long-term campaign to improve both: air quality and energy performance of equipment.
In this specific project, there have been 2 main objectives:
The data is collected from a variety of sensor packs (mainly IoT) and analysed on Energis.Cloud in order to:
- Optimise air quality of the working environment by ensuring constant temperature and humidity conditions within defined thresholds. Alerts are generated in case thresholds are about to be trespassed.
- Optimise security: alerts are generated in case fumaroles reach temperatures that could be dangerous.
- Measure savings achieved by recovering energy from fumaroles.
We asked Valentin Maerevoet, energy and facility manager at TEM, about the advantages of using the Enless hardware combined with the Energis.Cloud Software:
“Most campaigns in offices are the result of complaints of discomfort from workers. We install Enless probes and then analyse the data on the Energis.Cloud platform to have a clear understanding of the situation.
Most of the time, the results of the campaigns can reassure occupants: we provide neutral figures, meaningful graphics and a comfort score in relation to legislation. The building manager can then discuss with his staff, based on quantified elements, and find an agreement on the adjustment of the technical installations.
It also happens that major malfunctions are brought to light, for example unsuitable schedules causing the installations to run outside of occupied hours (at night and on weekends) or when this is not necessary (heating in the hot season). We can then, if the installations allow it, correct the adjustments of the installations and thus allow for significant energy gains directly. And if the installations do not allow these adjustments, we can propose solutions and make quantified offers to solve the problem.”