## 3 Project Case Study and Cooling Load Profile  
A district cooling project employing CCCPs located in Northeast Beijing, China is selected as a case study. Field tests were performed to obtain basic information and system operating data, including energy consumption, water flow rate, and temperature. Based on these data, several models were developed to simulate cooling loads and system operation; the results have been compared to the test data. Figure 2: Schematic diagram of distributed variable-frequency pump (DVFP) and water storage (WS) system. The entire project is a commercial district comprising twelve independent sub-buildings noted as S1-S12, neighboring the central cooling plant. The location of the sub-buildings, in addition to a topological diagram of the cooling water networks, is shown in Figure 3. The total floor area is 78,000 m\({}^{2}\). Most of these buildings are commercial buildings, including a cinema, restaurants, and retail stores. The time of operation of each of these buildings, which is shown in Figure 4, is dependent on their function. For example, buildings S2, S9, and S10 operate 24 h a day, whereas the other buildings only operate during daytime hours; furthermore, the opening time of each building is different. These characteristics significantly influence the load profile. Additionally, there are chillers fixed at each end-use building to generate chilled water; on-site investigation revealed that these chillers are of the same model (nominal cooling capacity = 700 kW and COP = 3.5). The tool used in this study to simulate cooling loads is a commercial software package named DeST, which has been proven to be useful in performing building load simulations [26]. Besides, there are many other simulation tools on the market and each tool has its own advantages. Many studies have focused on the use of efficient tool to perform effective energy profile simulation of buildings [27; 28]. The meteorological parameters are embedded in the software and 15 July is the full-load day (i.e., design day) in this study. All of the model settings, including building structure, materials, equipment, and lighting power density, are based on architectural drawings and the investigation of actual operation. This enabled simulation of the hourly cooling load of each sub-building on the design day. The hourly superposition of all of the building loads and a comparison with field test results are shown in Figure 5. The accumulated cooling load on the full-load day derived by simulation is 69,900 kWh, while the field test result is 68,100 kWh. It can be concluded that the simulation results are in agreement with the field test results. Thus, the modeling and simulation process are confirmed to be reasonable and can be implemented to calculate cooling loads under various conditions. The basic information for each of the sub-buildings is presented in Table 1, which also includes the peak cooling load and estimated cooling water flow, calculated at the \(\Delta\)T = 4.5 \({}^{\circ}\)C and COP = 3.5; these results are presented in the next chapter. The maximum cooling load for all buildings is 5500 kW, 70.5 W/m\({}^{2}\). Figure 3: Locations of sub-buildings and water networks. Figure 4: Operating schedules of S1–S12. Figure 5: Comparison between simulation and field test results for the entire district cooling project.