◆  Hotels, Motels and Accommodation Facilities  ◆ 

Hotels, motels and guesthouses require both room heating and cooling and a reliable domestic hot water supply.

Shower use is often concentrated in the morning and evening, creating high peak hot water demand. A wastewater heat recovery unit can recover heat from warm shower discharge to preheat incoming fresh water, reducing the heating energy required during these periods.

ZERO BOILER combines wastewater heat recovery, hot water storage and thermal storage to prepare for peak demand while supporting stable heat pump operation. Stored hot water also helps meet demand when wastewater heat is not yet available.

In summer, heat recovered from room cooling can be used to produce hot water. In winter, space heating and hot water production are managed within one integrated system.

Multiple standard units can be installed in parallel to suit the facility size and respond to changes in occupancy and energy demand.

Manage cooling, heating and hot water as one integrated energy system for the entire facility.

Winter Operation

1. The air source heat pump extracts heat from outdoor air to produce hot water.

2. Space heating and domestic hot water use separate water circuits and storage arrangements.

3. Underfloor heating or fan coil units (FCUs) can be selected to suit the facility.

4. Wastewater heat recovery preheats incoming fresh water, while hot water storage helps meet short periods of high shower demand.

5. Space heating operation is controlled according to the building’s heating load.

6. Initial sizing examples based on heat pump electrical input:

   • Approximately 330 m²: 10 kW class

   • Approximately 660 m²: 20 kW class

Final sizing requires assessment of insulation, climate, occupancy, hot water demand and storage capacity. Electrical input is different from heating output.

Summer Operation

1. Chilled water is supplied to FCUs for room cooling.

2. Heat removed from the rooms is recovered for hot water production.

3. Reverse-return piping helps balance flow between terminal units.

4. Cooling and hot water production are managed within one integrated system.

5. A brine circuit helps protect against freezing when its concentration is selected for local conditions.

6. Excess heat that is not required for hot water is released through the outdoor unit.

7. During cooling operation, control follows room cooling demand while recovered heat is used for hot water.

Cool the rooms, recover the heat and use it for hot water.

Compact Wastewater Heat Recovery Unit

1. Suitable for motels, hotels and small public baths.

2. Uses counterflow heat exchange designed to process the full wastewater flow, with wastewater and fresh water kept separate.

3. Targets a winter fresh water temperature rise of approximately 20–25°C, depending on operating conditions.

4. A simple configuration supports installation and maintenance.

5. Designed for long service life, with regular cleaning and inspection.

Recovering heat from shower wastewater reduces the remaining hot water heating load and supports the heat pump and storage system during peak demand.

Actual performance depends on wastewater temperature and flow, incoming water temperature, heat exchanger condition and the timing of hot water use.