Control system and method of controlling a refrigerator
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Solution Overview
Problem
Conventional methods for controlling refrigerated furniture in hotel rooms, such as minibars, fail to accurately predict guest habits, leading to noise annoyance, energy wastage, and inefficient operation due to the presence of staff or multiple key cards.
Innovation Solution
A control system and method that manages the refrigeration unit's operation through accumulation, inactive, timed, safety, and energy-saving modes, using temperature sensors and key card detection to optimize compressor usage based on guest presence and absence, ensuring minimal noise and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the compressor is switched off using a timer during nighttime hours, then noise disturbance is reduced, but the compressor may run during times when guests are actually awake, failing to address the real problem
Solution Approach 1:
The system uses key card detection to receive feedback about guest presence in real-time. When a key card is detected in the slot, the system knows guests are present and should not be disturbed. This feedback mechanism replaces the fixed timer approach with an adaptive system that responds to actual guest behavior patterns.
Solution Approach 2:
The system automatically adjusts compressor operation based on key card detection without requiring manual programming or guest input. The guest simply inserts their key card as normal, and the system self-adjusts to their presence, eliminating the need for guests to program timers or communicate their schedules.
2Object-affected harmful factors
If the compressor is disabled when a key card is inserted in the energy saver slot, then noise is prevented during guest stay, but the compressor cannot activate even when the room is empty if a key card is left in the slot
Solution Approach 1:
The system changes the operational parameters of the compressor based on key card detection. When no key card is present, the compressor operates normally to ensure food preservation. When a key card is detected, the compressor switches to silent mode. This parameter change approach allows the system to adapt its behavior to different conditions while maintaining reliability through the safety temperature threshold.
Solution Approach 2:
The system dynamically adjusts compressor operation based on real-time key card status. Rather than a static on/off control, the system continuously monitors for key card presence and adjusts compressor behavior accordingly, allowing it to respond to changing conditions such as guests leaving key cards in slots or staff entering rooms.
3Loss of energy
If the compressor operates in high energy saving mode when no key card is present for a long time, then energy consumption is reduced, but staff entry deactivates this mode causing energy wastage
Solution Approach 1:
The system activates energy-saving mode in advance when no key card is detected for a predetermined period. This preliminary action allows the system to prepare for extended absence scenarios while maintaining the capability to quickly respond if staff or guests enter later, thus preventing energy wastage while still achieving energy savings during genuine vacancies.
Solution Approach 2:
The system uses periodic key card checking to determine whether to activate energy-saving mode. By checking for key card presence at regular intervals and comparing against time thresholds, the system can distinguish between temporary staff visits and permanent guest absence, activating energy-saving mode only when appropriate while maintaining adaptability to changing conditions.
4Reliability
If the compressor maintains normal operation temperature, then food preservation is ensured, but energy consumption increases during periods of no guest occupancy
Solution Approach 1:
The system changes the temperature parameter of the compressor based on occupancy detection. When no key card is present for an extended period, the system raises the temperature setpoint to reduce energy consumption while still maintaining food safety. When guests are detected, the system returns to normal temperature operation to ensure optimal food preservation.
Solution Approach 2:
The system applies different operational qualities to different time periods and occupancy conditions. During confirmed vacancy periods, the system allows higher temperatures acceptable for short-term storage. During guest occupancy or uncertain periods, the system maintains strict temperature control for food safety. This local quality approach optimizes energy use without compromising food preservation reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively reduces noise disturbance, optimizes energy use, and ensures food preservation by dynamically adjusting refrigeration based on occupancy, addressing the limitations of prior systems.
Implementation Method 1
a refrigeration unit (4), adapted to subtract heat from said compartment (3)
Data Source
Figure 1
Figure 2
AI summary
A method for controlling refrigerated items of furniture (2), placed in a room and of the type comprising a compartment (3), configured to accommodate food (A) and beverages (B), and a refrigeration unit (4), adapted to subtract heat from the compartment (3). The method entails at least the following steps of: a. making the refrigeration unit (4) operate in an accumulation operating mode, in which the refrigeration unit (4) automatically maintains the temperature of the compartment (3) substantially at a first preset value, b. upon detection of the entry into the room of a person, automatically activating an inactive operating mode, in which the refrigeration unit (4) is switched off, c. after the refrigeration unit (4) has been made to operate in the inactive mode for a first preset time period, automatically activating a timed operating mode, in which the refrigeration unit (4) is kept active in at least one preset time slot, d. during the operation of the refrigeration unit (4) in the inactive mode or in the timed mode, upon detection of the exit from the room of the person, restoring the accumulation mode.