Dholera District Cooling Network Specs: DICDL HVAC Codes

1. Chilled Water Supply Parameters & Thermal Energy Storage (TES)

Centralized cooling plants generate chilled water using high-efficiency variable frequency drive (VFD) centrifugal chillers combined with Thermal Energy Storage:

• Chilled Water Temperatures ($4.5^\circ\text{C}$ Supply / $14.5^\circ\text{C}$ Return): Chilled water is pumped through subterranean distribution loops at a supply temperature of $4.5^\circ\text{C} \pm 0.5^\circ\text{C}$ and returned at $14.5^\circ\text{C}$, maintaining a high $\Delta T$ of $10.0^\circ\text{C}$ to maximize hydraulic thermal capacity.
• Thermal Energy Storage (TES Tanks): Central plants incorporate stratified chilled water storage tanks (capacity 30,000 to 50,000 m³). TES tanks are charged during off-peak night hours when electricity tariffs are low, discharging chilled water during peak afternoon heat demand to shave 35% off city grid power loads.
• High Efficiency Chiller COP ($\ge 6.5$): Central water-cooled centrifugal chillers must achieve an overall Coefficient of Performance of $\text{COP} \ge 6.5$ (equivalent to $\le 0.54\text{ kW/TR}$) under AHRI 550/590 rating conditions.

2. Pre-Insulated Twin-Pipe Distribution Loop

Chilled water is distributed across city zones through heavy-duty subterranean piping networks:

• Pre-Insulated Carbon Steel Conduits: Distribution mains utilize seamless or submerged arc-welded carbon steel pipes (ASTM A53 Grade B) insulated with rigid polyurethane foam (PUR, thermal conductivity $\le 0.026\text{ W/m}\cdot\text{K}$) and jacketed with a high-density polyethylene (HDPE) outer casing.
• Continuous Leak Detection Wire: Embedded inside the polyurethane insulation layer are copper alarm wires connected to DICDL’s SCADA system, pinpointing moisture leaks to within 1 meter accuracy.
• 16 Bar Design Working Pressure: Distribution loops operate at a nominal pressure rating of PN 16 (16 bar) with a minimum test pressure of 24 bar.

The table below outlines DICDL district cooling network technical specifications:

3. Building Energy Transfer Stations (ETS)

Instead of installing individual chillers, buildings connect to the district cooling loop via a compact basement ETS room:

• Plate Heat Exchangers (PHE): The primary district cooling loop transfers thermal energy to the building’s secondary HVAC loop through high-efficiency gasketed titanium or 316-stainless steel plate heat exchangers, physically isolating building water from the main municipal grid.
• Ultrasonic BTU Energy Metering: Every ETS room features a certified ultrasonic thermal energy meter measuring instantaneous flow rate and $\Delta T$, billing building owners per kilowatt-hour ($\text{kWh}_{th}$) or Ton-Hour of cooling consumed.

Frequently Asked Questions (FAQ)

#### What is the supply temperature of chilled water in Dholera’s district cooling network?

Chilled water is supplied from central plants at a temperature of $4.5^\circ\text{C}$ and returns at $14.5^\circ\text{C}$, maintaining an efficient $10^\circ\text{C}$ temperature differential ($\Delta T$).

#### How does a building connect to Dholera’s district cooling grid?

Buildings connect via a basement Energy Transfer Station (ETS) containing stainless steel plate heat exchangers that transfer cooling to the building’s air handling units without mixing internal and municipal water.

#### What energy savings does Dholera district cooling provide?

By using centralized high-COP chillers ($\text{COP} \ge 6.5$) and Thermal Energy Storage (TES) tanks, district cooling reduces peak electrical power demand by up to 35% compared to standalone building air conditioners.