## 5 Calculating the MUA's Energy Demand
### Annual Energy Demand with TCP Panels and Comfort Conditions  
Once the air renewal rate parameters above were obtained according to the CTE--air infiltration, surface temperatures, occupancy, etc.--and we had calibrated the model, we simulated the MUA's behaviour according to the two options described above. The possibility of incorporating solar thermal panels on the rooftop combined with TCP panels has been studied:  
OP1. All-air installation based on reversible air-air heat pump split system, model XPOWER VRF 2 Tubes (38 VT-168 HTEE) and air conditioner 39 SQ flow rate 1.8 m\({}^{3}\)/s by Carrier, with 148 kW cooling power and 162 kW heat power. Condenser and climate control in the MUA's conduit, with cold or hot air distribution throughout the building's whole volume. OP2. Installation of PPR capillary tube mats, in TCP panels, with an air-water heat pump model Aquasnap 30 RQSY039-160 by Carrier, 148 kW cooling power and 162 kW heat power similar to OP1, distribution of water to two distribution substations located in the MUA's conduits, and water distribution in the secondary circuit by a total of 24 independent PPR 32 mm in diameter circuits per  
Figure 9: Schematic diagram of the installation of capillary mats and fan-coil dehumidification modelled in Design Builder. floor, and ten fan-coils strategically located for air dehumidification, each with a cooling power of 2.5 kW. OP3. Installation of PPR capillary tube mats similar to that of OP2, with the same heat pump as above, and the ten fan-coils for air dehumidification, with a system of 230 m\({}^{2}\) of solar thermal panels, with absorption cooling, chemical energy (solar cooling). They provide alternative energy to the system. Table 2 shows the results of thermal loads, solar gains by glazing and internal thermal loads for OP1 and OP2. They can be observed to be very high, boosted by the presence of giant rooftop skylights lacking protection, despite having been later covered with sandwich panels. As can be seen, using TCP panel radiant systems would reduce these thermal loads by 18% in the case of the OP2 radiant floor, and by 17.2% in the case of the radiant wall. The most decisive factor, apart from the energy provided by the equipment located inside the MUA, was the indoor air temperature \(T_{i}\), increase in summer and decrease in winter, with similar comfort levels to that of convective systems, which produces a substantial decrease in heat flows by \(U\) transmittance on all exterior walls. Table 3 shows the results by simulating summer, winter and annual energy demands for the three options OP1-OP3. These values are similar to those usually experienced in office buildings, in which 30% and 35% energy savings compared to convective systems were accredited in Central Europe [38]. In our case study, the simulations produced notable annual energy saving values. Annual energy demand was 130.83 kWh/m\({}^{2}\)y for the all-air system currently adopted, and 98.25 kWh/m\({}^{2}\)y for the TCP ceramic thermal panels underfloor system (OP2), accounting for 24.91% in energy savings. These reductions are of the same order of magnitude as those obtained in other studies [21,38]. In the case of radiant wall or ceiling systems, energy demand reductions were somewhat lower [1]. Figures 10 and 11 show the temperature gradients produced in the simulation in different areas of the house for both the OP1 and OP2 conditioning system options, which show homogeneous temperatures in the occupancy area for Radiant Systems. In addition, the indoor air temperature \(T_{i}\) was about 3 \({}^{\circ}\)C higher in summer and 2 \({}^{\circ}\)C lower in winter.