  The proportion of Energy consumption in the building industry is great, as
well as the amount of cooling and heating system. Scholars have been working on
energy conservation of Heating, ventilation, and air-conditioning and other
systems in buildings. The application of occupant behavior data for building
energy optimization has started gaining attention from scholars. However,
occupant behavior data concerns many aspects of occupants' privacy. Different
types of occupant behavior data contain occupants' private information to
different levels. It is crucial to conduct privacy protection of occupant
behavior data when using occupant behavior for energy conservation. This paper
presents the aspects of privacy issue when using occupant behavior data, and
methods to protect data privacy with blockchain technology. Both two options of
using blockchain for privacy protection, sending data records as transactions
and storing files on the blockchain, are explained and evaluated with
temperature records from an open access paper. Sending data as transactions can
be used between sensors and local building management system. While storing
files on blockchain can be used for collaboration of different building
management systems. Advantages, drawbacks, and potentials of using blockchain
for data and file transfer are discussed. The results should be helpful for
using occupant behavior data for building energy optimization.
