Holtop HFW-980HA1 Vortex Module-Type Air-Cooled Chilled Water (Heat Pump) Unit The Holtop vortex module-type air-cooled chilled water (heat pump) unit utilizes advanced modular technology with air as the cooling/heating medium. This integrated central air conditioning equipment serves as both a cooling/heating source and combined unit, compatible with fan coil units, cabinet-type air handlers, ceiling-mounted units, and fresh air systems to form semi-centralized air