Optimal insulation thickness in historic buildings with a heat pump as an energy source

Abstract

Improvement in the thermal performance of the historic buildings can possibly lead to a reduction in the energy they need to operate. Thus, the negative impact of such buildings on the environment can be mitigated. Generally, any kind of works that would modify the looks of the façade of historic monuments is forbidden, that is why their thermal upgrading must be carried out inside. This process is usually more expensive because it requires individually selected materials and technologies. This study shows the analysis carried out to select the optimal insulation thickness with respect to the total costs of the electrical energy consumed to run the pump and the costs of thermal upgrading of the walls. Based on the example of natural cork panels with thermal conductivity of 0.04 W/mK and polyurethane foam boards with drywall finish at one side (λ=0.022 W/mK), the optimal insulation thickness was determined for five-year duration of the investment loan at 5% fixed interest rate. In the calculations, local climate conditions are taken into account.