A Heat Pump-Based Multi-source Renewable Energy System for the Building Air Conditioning: The IDEAS Project Experience

Abstract

The current paper presents the state-of-the-art of the ongoing IDEAS research project, funded under the Horizon 2020 EU framework programme. The project involves fourteen partners from six European countries and proposes a multi-source cost-effective renewable energy system for the decarbonisation of the building envelope. The system features a radiant floor fed by a heat pump for the building thermal management. The heat pump can exploit sun, air, and/or ground as thermal sources through the use of photovoltaic/thermal solar panels, air heat exchangers, and shallow ground flat-panel heat exchangers. Thermal energy storage is achieved by means of phase change materials spread along several system components, such as: radiant floor to increase its thermal inertia, solar panels for cooling purposes, ground to enhance soil thermal capacity. Within the project framework, a small-scale building, featuring a plethora of sensors for test purposes, and two large-scale buildings are meant to be equipped with the renewable energy system proposed. The small-scale building is currently in operation, and the first results are discussed in the present work. Preliminary data suggest that while multi-source systems coupled with heat pumps are particularly effective, it is complex to obtain suitable thermal energy storages on urban scale.

A Management Strategy for Multi-Source Heat Pump Systems

“…In the secondary loops, a pump (P1) feeds the different free sources and additional one (P2) is used for the secondary user loop connected to a radiant floor system and to three fan coil units. A number of three-way valves allow switching between the exploitation of the different renewable heat sources [13], either in parallel or in series, to thermally recharge and feed the tank BF1 on the sources side of the HP. A scheme of the system and its devices is shown in Figure 1.…”

“…Two guard rooms (3m 2 floor, 8m 3 volume) on the east and the west sides of the test room are kept at a controlled temperature by dedicated fan coil terminal units. The purpose of the PCMs is to enhance the thermal inertia of the floor so that, once the material is thermally charged, it can still heat or cool the room for long time even when the pump is off [13].…”

“…An example of the GHX installation is shown in Figure 3. More details about this installation are reported in the study of [13].…”