Heating Upgarad at the Rose Lake Plant Materials Center

STATEMENT OF WORK GREENHOUSE HEATING REPAIR AND MODIFICATION Problem Statement The greenhouse heating at the Rose Lake PMC is currently inoperable due to a leak in the rubber tubing in the radiant floor heating system. The leak's probable cause was due to uneven shifting of the cement pad that encases the rubber tubing. The location of the leak is currently unknown and the radiant floor heating system will be abandoned. The current greenhouse will be effectively separated into east and west zones. The desired heating installation on the east side of the greenhouse would include an under-bench finned pipe convection and radiant heating system. This fin pipe system would connect to the existent centralized boiler system and be installed under two 6 x 40 foot greenhouse benches. Because this under-bench heating system will not provide all the required heat for the greenhouse, there will be the installation of low-intensity infrared tube heaters at the peak of the greenhouse, running the length of the 50' long house. One additional suspended unit heater will also be purchased and installed in the west side of the greenhouse to replace an older heat unit. Performance for the under-bench fin heating, tube heaters, and suspended unit heater should be at the highest efficiency standard for the industry. The combination of heating systems will allow more flexible temperature control and improved energy efficiencies, especially when managing half the greenhouse. Along with the required heating unit installation, the vendor will need to purchase and install an industry-standard thermal, greenhouse heat retention wall curtain for dividing East and West growing zones. Ideally, this roll up wall partition would be driven electrically, but if the electrical operators are space or cost-prohibitive, a manual operator can be substituted. Improvements to the cooling system venting are also required. All 4 exhaust fans will need bearings replaced in fan blades and perhaps motors replaced to improve functioning and performance. The ceiling ventilation assembly does not open or shut completely and will require carrier bearing replacement. Scope of Work The contractor shall provide all labor, materials, supplies, tools, equipment, transportation, facilities, expertise, and supervision as necessary to repair greenhouse heating system for a 1,152 square foot greenhouse. All work shall conform to all local, state, and national building code requirements for greenhouse installation. 1. Fin Pipe, Piping Materials, and Boiler Piping materials should be compatible with use of existent functioning indoor Raypak Hydronic Heating Boiler model# GHB-4 (H-183) with a 186.0 MBH input. If a new, higher efficiency boiler system needs to be purchased and installed for greater compatibility with the under-bench system, the vendor should include this cost in the price estimate. If piping insulation is required to deliver necessary heat load, then the vendor cost estimate should include cost for insulation materials and installation. The under-bench fin system should provide required heat quietly and efficiently. 2. Radiant Tube Heaters Two new 2-stage low intensity tube heaters will be installed on the east half of the greenhouse. These infrared tube heaters will be fueled with propane, and will provide approximately 50,000 BTU/h (low fire)-65,000 BTU/h (high fire) to the greenhouse. The tube heaters will be installed at a clearance height specified by product and industry standards, and would be ideally situated above and between the two 6 x 40 foot benches so as not to be placed directly over a bench, but over the cement flooring. The current greenhouse dimensions are a wall height of 8' and gable height of 5.5'. Two tube heaters 20' long, or an equivalent arrangement would be suitable. Two 2-stage digital programmable wall-mounting type thermostats will be provided with a 50-90'F operating range. The installation and connection of gas-fired radiant heaters, and associated fuel and venting features and systems shall be installed in accordance to applicable local, state, and federal codes and regulations, and per manufacturer's written installation instructions and specifications. 3. Suspended Unit Heaters The existent gas-fired Modine unit heater model # PV200 with functional output of 160,000 BTU/hr shall be replaced with 1 comparable, newer propane suspended unit heater. The unit must be installed in a horizontal position with appropriate clearance according to industry safety standards. Horizontal unit heaters will be preferred to vertical configurations. The air stream from the unit heater shall be free from interference as much as possible to allow for satisfactory heat distribution. 4. Roll-up Curtain System A greenhouse roll curtain system will be installed for dividing East and West growing zones to increase efficiency and reduce heating costs. Ideal models will have electric controls and be motorized. Preference is given for curtains with weighted bottoms that eliminate billowing. COOLING VENTILATION The contractor shall provide all labor, materials, supplies, tools, equipment, transportation, facilities, expertise, and supervision as necessary for repair and modification of 4 cooling exhaust fans and greenhouse ceiling ventilation assembly. All work shall conform to all local, state, and national building code requirements for greenhouse installation. 5. Exhaust Fans All 4 exhaust fans (American Coolair Co.) have high-torque AO Smith fully-enclosed belted- fan motors. Initial inspections have found these fans inoperable due to faulty bearings. There may be other unidentified defective parts, and the units may need to be disassembled to further assess the source of equipment failure. The noise level of the fans will be reduced where it is economically practical. This may involve tightening or replacement of worn belts and cleaning motor and fan components. 6. Ceiling Ventilation The ceiling ventilation assembly does not open nor shut completely and will require carrier bearing replacement. The rack and pinion setup will need realignment and timing adjustment. If the teeth of the vent rack are worn or broken, or the vent rack is bent or misaligned, a new vent rack will need to be purchased and installed.