The IceBox Challenge

Written by Muhab Tomoum

The IceBox Challenge is a contest run by Passive House Canada with support from the City of Vancouver to demonstrate a new construction method that can reduce energy consumption by up to 90% effectively reducing our carbon footprint. The demonstration consists of two 1 tonne blocks of ice left outside in the sun for 18 days. One box is built according to the BC building code and the other is the passive house standard. How much ice is left shows how well the design keeps out the summer heat.

Mistywest was assigned with the task of monitoring the internal and external temperature of the boxes, in addition to sensing the mass of the ice. So i designed a circuit that gathers the data using load cells and temperature sensors and sends it via 2g cellular network to a server. A webhook would then pull that data and display it on the competition’s official website. I also set up personal access from an app on my phone to be able to pull in live readings to help with installation and verification.

Installation

The boxes were installed on July 27th, 2017 at the Olympic Village Square, Vancouver. With the help of the construction team we successfully installed the sensors on site. I then calibrated the sensors and waited for the arrival of the Ice blocks. The Initial readings of the mass were about 976 kg in each box. As expected the temperature inside the boxes slowly started to decrease as the boxes were reaching equilibrium and the ice cooled off the air inside. After one day the passive house standard settled at 4.7 °C and the BC building code at 5°C.

Results

The competition was a huge success. Once the ice blocks were unveiled on the 14th of August it was quite evident that the passive house standard had retained much more of the ice in fact it had 639 kg left compared to 407 kg at the BC standard. It had about 63% less ice melted which is a staggering number given that outside temperatures reached up to 32 °C during that period.