Installation/Operation Instructions PlaneAC 2.0 Air Conditioner Plane Comfort LLC support@planeac.org Overview The PlaneAC 2.0 is an electrically powered air conditioning unit. It uses microchannel heat exchangers and the latest in high efficiency components for maximum efficiency. The AC unit can run on aircraft power only, on battery power only, or on both. The battery is internally isolated from the aircraft power and they will not cross-feed. The 14v version runs on 12-14v and can provide about 7500 BTUs of cooling at 58 amps* while moving about 550 CFM of air – about 275 exhaust and 275 of recirculated, cooled air. Power draw ranges from 1-50 amps DC per input, with a combined maximum draw of approximately 58 amps. The minimum power draw with the compressor running is about 25 amps. Due to the aircraft having a higher voltage than the battery, the air conditioning unit will pull some power from the aircraft and some from battery if both are connected simultaneously and the aircraft alternator is not generating enough power by itself (e.g. low engine RPMs). The air conditioner can be added or removed based on mission requirements (useful load, baggage space, etc). Note that supplementary battery power or a Plane Power high output alternator is recommended for the 14v model as factory 14v power systems (usually 50A alternators) just don’t generate enough power. If you use a battery, it must be rated for 50 amps of continuous power draw. Only a few batteries on the market meet this specification right now. We do not sell these batteries directly but can point you to vendors who do. We have tested https://battlebornbatteries.com/ 14v 50Ah units with success for this purpose. The LiFePO4 battery chemistry they use is supposed to be the safest available. For safety, all custom plastic parts are made from fire-retardant ABS, all internal insulation is made from fire retardant materials and almost all wiring is aircraft-grade EFTE (except where required for mechanical flexibility). * Exact BTU number varies based on temperature, humidity, power setting, exhaust pressure from the empennage, etc, however we do not inflate the numbers. BTUs and CFM ratings are based on realistic calculations and real-world measurements. Plane Comfort LLC support@planeac.org Installation considerations Please work with your A&P on all aspects of the installation. In our experience these can all be considered minor alterations, but that is ultimately up to your specific A&P to make that determination. The AC unit has four main install considerations: Power Both the 14v and 28v units will draw a steady 50 amps from aircraft power at max settings. Please ensure your aircraft alternator(s) are capable of supplying this amount of power plus enough for your aircraft systems such as lights, radios, GPS, etc. Have your A&P run a load analysis. The units will reduce draw if low voltage is detected, but you will still need healthy alternators with good power output. The power circuit should be wired with at least 6ga wire from the main bus. Circuit breakers are built into the AC unit itself although an additional one should likely be installed near the power source – consult with your A&P. The wire is terminated with a SB50 with 5900-BK 6ga inserts (included). Connector Datasheet. Suggested ring terminals for aircraft breaker wiring are #8 stud size and 6ga wire. Both Panduit P6-8R-T and Molex 19193-0243 are available from Mouser and fit this specification. A compatible 50A breaker is W23-X1A1G-50 and is available from both Mouser and Aircraft Spruce. Power connector Plane Comfort LLC support@planeac.org Waste heat - The waste heat from the condenser (bottom half of the unit) must be vented from the aircraft. This can usually be accomplished via a hole in a non-structural rear baggage panel and allowing the heat to vent through the empennage. Some empennages have enough airflow to accommodate the exhaust and some do not. Please evaluate this for your specific aircraft. If louvered inspection panels or other empennage airflow enhancements are available for your aircraft, strongly consider them to help with airflow. Being unable to vent enough waste heat will result in reduced cooling capacity and compressor shutdown if heat or pressure rise too much. We have included 127mm / 5in flanges for connecting the blue exhaust hose to the selected mount point. They can be secured to a rear bulkhead with M4 hardware or other hardware of your choice. Flange Condensation drain – You will need to do something with the condensate. We highly recommend running a drain tube to the bottom of the aircraft. In humid air there can be a significant amount of condensate pulled from the air (1 gal/hr). Speed/power control – Compressor and fan speed, and therefore power draw, are regulated via the included control unit. The included cable for this can be loose for ease of removal, routed under the carpet, etc per your choice and in agreement with your mechanic. The control cable itself uses five 22ga wires and connects to a Molex Mini-Fit Jr part 3901-2065 at the AC unit side and Molex Micro-Fit (part 43025-0600, terminals 043030Plane Comfort LLC support@planeac.org 0008) at the control unit. It is bundled in a fire-resistant sleeve OR is a ETFE-insulated shielded wire bundle that conforms to MIL-C-27500. Operation There are two main controls on the control unit. One is a battery switch, which turns on battery power. The other is a combination switch and dial. The switch (a counter-clockwise detent) turns on aircraft power and the dial is used to set the desired cooling level / power draw. Control Unit If only the battery switch is turned on, the AC unit will default to a pre-cool mode which is basically a 100% power setting. If both battery and aircraft power are turned on, the AC unit will use your selected speed setting. If you have a battery attached and the engine is running, this is the recommended setting. On startup the compressor will run at half speed for about 40 seconds to ensure proper compressor oiling. This is automatic and cannot be overridden. During this time the 14v AC unit draws about 35 amps of power if the fans are at about 50% speed, as low as 30 amps if the fans are lower and up to 40 amps higher if they are set to max. After this period the compressor can be run anywhere from the lowest to highest setting. The lowest setting draws about 4 amps as it turns off the compressor and only runs the fans on a low setting. Increasing the setting slightly engages the compressor. Note the above ~40 second startup occurs every time you turn on the compressor. The air conditioner will automatically regulate power draw to ensure a maximum of 50 amps is pulled from each input. Fan speeds will remain at their selected levels but the compressor speed will be reduced as required. Plane Comfort LLC support@planeac.org The air conditioner will automatically reduce power draw, including completely shutting down the compressor, if aircraft voltage level drops too low, indicating power draw is exceeding alternator capacity. When voltage levels increase again, power draw will gradually scale back up. This can happen during idling, high power draw configurations (lots of lights on, pitot heat, etc), and landing when power is pulled back all the way to idle. If you are having issues with the automatic low voltage regulation please let us know and we can work with you to tune these functions. Different aircraft have differing power generation abilities. Note that in some circumstances, especially on 14v aircraft, you may get a low voltage situation even without an air conditioner if you have a high system load and low power setting (for example, turn on landing lights, pitot heat, etc, then pull throttle). Troubleshooting Insufficient cooling • Try removing the exhaust hose. Check the exhaust fan is working. If it is working and removing the hose results in cooler air being blown from the cold air outlet, you likely have too much backpressure from the empennage and the AC unit is unable to exhaust the waste heat. Explore additional airflow/venting options. o For Cessna, look at louvered inspection panels such as the Airflow Enhancement System from Aircraft Spruce. o For Beechcraft, later models (74+?) have a cabin air exhaust port in the empennage that could be disconnected from the hat shelf vent, providing empennage ventilation. There are reports this can be retrofitted into earlier models (35-554035-37 SCOOP ASSY AIR VENT). o Owner-created inspection panels with louvers (with A&P approval) • Verify evaporator fans (on the top) are working. Placing and removing the unit Unit placement and removal is as follows: 1) Slide it in on the side without connectors, then set it upright. Try to use a soft surface such as towel or mat as a sled so the paint on the AC unit does not scratch on metal sills, nuts, etc. 2) Plug in the control cable, power cable, condensate drain tube and exhaust hose. 3) Like any other cargo/baggage, secure it to available tie-down rings in the baggage area in case of turbulence. Plane Comfort LLC support@planeac.org 4) Don’t forget to add it to your weight and balance computations. The unit weighs 50 lbs (23 kg). Plane Comfort LLC support@planeac.org
