Building Management Systems / Cogeneration / Conto Termico / EcoBonus / Energy Management / Engineering / Revamping thermal plants / Smart Monitoring
Efficient transformation of energy in the hospitality sector: best practices and success stories
Alessio Cividini, Head of Energy Management – SGR Efficienza Energetica
The transition to low-consumption systems is becoming increasingly crucial in all business sectors (from residential to the process industry) in which the use of energy resources and associated economic and environmental impact is significant.
The path towards more sustainable and rapidly growing models can be mapped out in four basic steps. It is basically a process of continuous improvement, accompanied by a growing awareness and knowledge of energy conversion in the use of facilities, plants and processes.
The main steps of this approach, resulting in a progressive decarbonisation of activities, are briefly outlined below, starting with an initial fact-finding survey, moving on to the measurement of consumption, then actions aimed at moderating energy carriers and, finally, the measurement of results achieved.
The process can be repeated over time, setting increasingly ambitious goals.
Leaving to one side the energy audit phase, which would require a chapter in its own right, we give here a brief overview, supported by field analysis, of potential efficiency improvement actions in the specific case of tourist accommodation facilities.
The first form of active intervention, which is highly recommended and can be undertaken at a modest cost, consists of the implementation of systems for the continuous measurement and analysis of energy consumption. This is crucial for gaining a greater knowledge of the extent to which energy carriers are used and transformed on-site.
Briefly summarising potential, we can identify:
- real-time monitoring of energy absorption, singling out criticalities and possible anomalies
- definition of customised energy performance indicators (EnPIs) for the site, unit and plant to pinpoint deviations from target performance, comparative energy analyses and multi-site benchmarking
- analysis and comparison with historical data in order to detect any deviations from historical trends
- possibility of setting automated alarms after having established specific consumption thresholds
- regular reporting of performance monitoring, and reporting of savings resulting from any energy efficiency improvement actions
Sufficient periods of monitoring can therefore help to identify interventions that may allow a reduction in the energy actually required to meet the facility’s needs (maintaining comfort conditions, hot water production, lighting, food preparation and storage, etc.).
The table below gives a summary of some of the possible improvement actions aimed at moderating energy demand.
Table 1 Actions to raise energy efficiency on the demand side
| Type of action | Intervention | Benefits | |
|---|---|---|---|
| Improvements to building envelope | Insulation | Insulation of opaque elements (perimeter walls and roofing), replacement of windows and doors with high thermal performance components. | Reduction of thermal needs for winter and summer air conditioning Improvement of comfort conditions |
| Shading systems | Installation of fixed or mobile shading systems (possibly managed using advanced control and automation systems) | Reduction of solar penetration in summer months, with consequent reduction of air conditioning needs | |
| Painting of roofing | Painting the roofing surfaces of building structures in white or bright colours | Reduction of solar penetration in summer months, with consequent reduction of air conditioning needs | |
| Control and automation systems | Building Management Systems (BMS) | Automated management of room systems (presence sensors, window opening, bedroom opening) | Reduced switching on of lights and of heating and cooling systems when not necessary, resulting in reduced consumption for air conditioning and lighting |
| Raising the efficiency of HVAC systems | Heat recovery | Installation of heat recovery units serving air handling units | Reduction of requirements for heating and cooling fresh air |
| Fans and pumping units | Replacement of existing motors with new high-efficiency units and/or installation of frequency control inverters | Reduction of electricity requirements for circulating the heat-carrying fluid in the air-conditioning system | |
| Power quality | Testing survey | Measurements with portable instrumentation for the acquisition and analysis of the main electrical parameters (voltage, power factor, harmonic distortion, etc.) | Identification of the most critical areas of the electrical system and definition of possible interventions |
| Voltage optimisation | Installation of supply voltage control systems to limit voltage fluctuations | Reduction of power consumption Reduction of wear and tear and breakdowns of electrical equipment | |
| Local or centralised power factor correction | Installation of power factor correction systems to reduce reactive energy absorption from the grid | Reduction of penalties charged by the electricity supplier Reduction of currents circulating in the system (less wear and tear and failures of electrical equipment and conductors) | |
| Efficient lighting | Low-consumption light sources | Replacement of inefficient lamps (incandescent, fluorescent, etc.) with high-efficiency LED sources | Reduction of electricity requirements for room lighting Improvement of room comfort |
| “Advanced” control | Installation of sensor-based switching and lighting level control systems (dusk sensor, presence, lighting conditions) | Reduction of electricity requirements for room lighting Improvement of room comfort | |
| Low-consumption equipment | Preparation and storage of food (food & beverage) | Replacement of outdated and energy-consuming equipment (ovens, cold storage rooms, chest freezers, etc.) | Reduction in gas and electricity consumption |
| Lifts | Installation of energy-efficient lifts | Reduced power consumption Reduced maintenance costs | |
After assessing and implementing measures aimed at limiting requirements, the energy-saving potential offered by the ‘free’ contributions of renewable sources absolutely has to be tapped, meeting a portion of consumption needs through green systems having a reduced environmental (and economic) impact. Existing generating systems also need to be modified to meet remaining needs through the more efficient transformation of energy carriers.
| Type of action | Intervention | Benefits | |
| Energy production from renewable sources | Solar thermal | Installation of thermal solar panels for meeting hot water needs and for heating swimming pools | Reduced thermal needs for heating water |
| Photovoltaic solar and electrochemical storage systems | Installation of photovoltaic solar panels for on-site electricity production and self-consumption Installation of storage systems for storing the energy produced |
Reduction in electricity drawn from the grid Possibility of using renewable energy during evening hours | |
| Efficient production systems | Combined production of electricity and heat | Installation of cogeneration systems to produce electricity for self-consumption, with simultaneous heat recovery | Reduction in electricity drawn from the grid Production of hot water through recovered heat |
| Revamping of thermal units/cooling units | Replacement of thermal units with new high-efficiency condensing boilers or heat pump systems (with possible use of geothermal energy or lake water) possibly hybrid systems | Reduction in energy consumption |
Case history
Here we illustrate a real-life case of energy efficiency intervention in a tourist accommodation facility, a 4-star hotel open all year in Riccione, a municipality located in the province of Rimini. The facility in question has 108 bedrooms, dining rooms, swimming pool, conference centre and a surface area in excess of 6,500 square metres, hosting an average of 60,000 visitors per year.
After carrying out an energy audit to gauge the current situation and identify potential efficiency measures, a 20 kW micro-cogeneration plant was constructed on the roof of the building to produce electricity on-site intended for self-consumption, while at the same time recovering heat for the production of hot water, used to meet the hotel’s thermal needs.
The constructed system was then monitored during the operating period 2018 – 2020, analysing the monthly energy balance and assessing the contributions of the new cogeneration plant.
Below is a comparison of the annual values estimated during the preliminary energy audit and those actually measured (to date) using an ad hoc metering system.
| Audit | 2018 | 2019 | 2020 | 2021 | |
| Hours of operation (h) | 4.686 | 7.855 | 8.246 | 4.618 | 6.329 |
| Electricity produced (kWh) | 93.720 | 132.557 | 145.951 | 77.233 | 107.875 |
| – of which self-consumed (kWh) | 93.608 | 131.528 | 145.274 | 76.042 | 103.675 |
| – of which sold (kWh) | 112 | 1.028 | 677 | 1.191 | 4.200 |
| Heat recovered (kWh) | 187.440 | 256.990 | 287.520 | 150.680 | 208.700 |
| Gas consumed (Smc) | 30.506 | 46.551 | 51.726 | 27.148 | 37.637 |
The cumulative savings in terms of primary energy (toe) and CO2 not emitted was then reported.
Finally, looking at economic benefits achieved, a comparative analysis between estimated cumulative annual savings during the audit phase and those recorded during the plant’s operation is reported.
In terms of payback, the initial calculation forecast a return on investment in 8 years, the latest estimate (extrapolating over the following years the average annual savings for the period 2028-2021 management) points to payback in approximately 7 years.
The cumulative cash flow (CF) trends in the two scenarios are shown below.
