November 17, 2008 ILC08 HVAC and VE Update November 17, 2008 ILC CFS Workshop 2008 Chicago Lee Hammond, Fermilab Global Design Effort

November 17,2008 ILC08 Global Design Effort 2 RDR to VE RDR - Air treatment Design Basis Tunnel Ventilation – Conditioned dehumidified air from surface mounted equipment is ducted into the service tunnel at each shaft. A volume of 25000m³/h (15000cfm) flows at approximately 27m/min (88fpm) to the midpoint between shafts where it is routed into the beam tunnel and returned to the shaft area. Fresh air at a rate of 20% (air change/16hr) is mixed into the air then conditioned and it is recirculated back to the service tunnel. Air volumes for the DR and BDS are similar. Hazardous Conditions - The air direction is reversible and capable of being doubled (unconditioned) during hazardous situations. Design temperature ML - The design temperature for the ML service and beam tunnels is 27-32°C (80-90°F). ML electronics' heat rejection is mainly to CHW direct cooling and FCUs with small amounts of heat to the ventilation air. AHU and FCUs are used at alcoves and shaft areas. Design temperature DR - The design temperature for the DR tunnel is 40°C (104°F), using process water fan coil units, and the tunnel wall as a heat rejection source.

November 17,2008 ILC08 Global Design Effort 3 RDR to VE RDR - Air treatment Design Basis Design temperature BDS - The design temperature for the BDS is 29-32°C (85-90°F). The low “heat to air” load is mainly absorbed by the tunnel wall. Air mixing fans will be used for temperature stability as required by the BDS. Used the basis that airflow could pass from the service tunnel to the beam tunnel through fire/smoke/ODH/radiation protected passages between the tunnels. This assumes that radiation/oxygen deficiency hazards (ODH) do not exist or can be mitigated between the tunnels from the standpoint of air mixing. This item needs concurrence from rad/ODH groups. AHU and FCU sizes in the alcoves and tunnels did not consider heat absorption by the rock wall. These units use chilled water from the surface as the heat rejection source.

November 17,2008 ILC08 Global Design Effort 4 RDR to VE Fan Coil Unit (FCU) rationalization CHW Fan coil units are the most efficient way to pick up the large “heat load to air” in the tunnel. Heat loads to air were too great (at 26kw/RF at RDR then 21kw/RF post RDR 12/07) to be cooled solely by surface equipment. That’s 1-1.5MW in a 2.5km tunnel section. Stabilizes temperature gradients. For example a 13mm (1/ 2”) pipe with CHW can remove 3.5kw of heat by contrast it takes 250mm (10”) air duct. At the upper limit of industry standard flowrates…to cool 1000kw (286tons) requires 78m³/h (343gpm) or m³/h (160000cfm). Either 100mm (4” pipe) or 3.7 m² (40sqft) duct…2.1m (7ft) diameter at 1200m/min (4000fpm)… 72km/hr (45mph) Eliminate CHW without greatly reducing the heat load…next step is to use Process water FCUs and/or compressorized self contained rack cooling equipment for heat rejection. This equipment requires approx 30°C (85°F) process water for heat rejetion.

November 17,2008 ILC08 Global Design Effort 5 HVAC VE Update Not considered at this stage due to the small percentage of total load. CHW Fan Coil Units are needed to maintain tunnel temperatures.

6 Air System Concept Shaft 7 Service tunnel Beam tunnel Approx RF in 2.5kw section Neutral air, 25000m³/h (15,000cfm) 30°C 30°C (85°F) Fan coil Units

November 17,2008 ILC08 Global Design Effort 7 HVAC VE Update VE #1 – Investigate use of desiccant dehumidifiers VE #2 – Modify top-of-shaft HVAC to only process make up air, add blowers at tunnel level for recirculation VE #3 – Centralize the HVAC and reconfigure airflow from tunnel ends or center VE #4 – Utility built HI-efficiency cogen power/cooling plant on site and distribute power and 0.6°C (33°F) CHW throughout the facility –Subpoint Sub, sub point

November 17,2008 ILC08 Global Design Effort 8 HVAC VE Update VE item #1 – Investigate use of desiccant dehumidifiers Desiccant dehumidifiers are efficient at providing very dry air. They are designed to provide humidity levels much lower than required for the ILC tunnels. Preliminary investigation revealed the cost for this equipment to be in a range of twice the cost of refrigerant based dehumidification equipment. They also require higher energy use.

November 17,2008 ILC08 Global Design Effort 9 HVAC VE Update VE item #2 – Modify top-of-shaft HVAC to only process make up air, add blowers at tunnel level for recirculation The advantages to this configuration would be to reduce duct sizes in the shaft and reduce the surface equipment size and presence at the surface. Air purge during hazardous conditions would not allow a ductwork size reduction. The tunnel air conditioning units would be moved to the bottom of the shaft area requiring additional alcoves and heat rejection medium whether its chilled water or process water. Shaft 7 Service tunnel 85 F AHU

November 17,2008 ILC08 Global Design Effort 10 HVAC VE Update VE item #3 – Centralize the HVAC and reconfigure airflow from tunnel ends or center Though not specifically detailed this VE suggestion would still require injection of conditioned fresh ventilation air at every major shaft as a minimum to comply with ventilation codes. This configuration assumes that FCUs and AHUs would be needed to condition the air for proper tunnel temperature. FRESH AIR

November 17,2008 ILC08 Global Design Effort 11 HVAC VE Update VE item #4 – Provide one hi-efficiency cogen power/cooling plant on site and distribute power and 0.6°C (33°F) CHW throughout the facility: Removes power/CHW production systems costs from the project cost. Removes one piping system from project. 0.6°C (33°F) CHW = smaller pipes, lower HP pumps, smaller HXs, very HI delta T (50°C/90°F) Cogen plant builder/operator finances, builds, operates, and maintains power plant then sells utility power and CHW to ILC and possibly other customers. Allows cooling of tunnel and electronics mitigating high temperature disadvantages. Centralize plant reduces shaft/support area footprints

November 17,2008 ILC08 Global Design Effort 12 HVAC VE Update Air Treatment is about 1% to 5.5% of CFS construction cost estimate depending on where the CHW systems are located. If CHW is eliminated then the air refrigeration systems would be in the Air Treatment WBS. RDR

November 17,2008 ILC08 Global Design Effort 13 HVAC VE Update Summary –Subpoint Sub, sub point

14 CFS Air Treatment Layout