RV air conditioning system principle and technical points
RV air conditioning and household air conditioning refrigeration system principle is similar.
Its refrigeration system mainly includes four parts: compressor, condenser, throttling system and evaporator.
Compressors are mainly divided into piston type, rotary type and scroll type. Considering factors such as RV power supply, power consumption and line design, RV air conditioning should be low current and low cooling power, so rotary compressors are mainly used.
Rotary compressors include single cylinder and double cylinder. Let's take a look at their respective advantages and disadvantages:
1. Vibration and noise: Double cylinder vibration is better than single-bar compressor, small displacement effect is slightly smaller, large displacement effect is obvious, see subsequent comparison. Noise level is equivalent
2. Performance: Double cylinder compressor has a large leakage area, large clearance volume, low cooling capacity, and slightly lower performance.
3. Reliability: Double cylinder compressor has many parts, eccentricity is difficult to control under assembly process, and reliability is slightly poor.
4. Cost: Double cylinder compressor has many parts (middle plate, cylinder, etc.), complex process assembly and high cost.
It can be seen that in the case of low-power refrigeration requirements, the characteristics of the two-cylinder compressor are not obvious, and due to the continuous improvement of machining accuracy, the precision of the matching of single-cylinder compressor parts has been improved, and it still occupies the mainstream of the market.
In addition to the compressor, the condenser and evaporator and the matching fan also have a key impact on the actual refrigeration. From the above figure, it is not difficult to understand that the larger the area of the condenser and evaporator, the larger the air supply of the fan, the better the actual refrigeration effect!
Refrigeration capacity is an important indicator for everyone to choose air conditioners, but it is necessary to distinguish whether it is the maximum cooling capacity, nominal cooling capacity, or rated cooling capacity.
As a motorhome application, in addition to paying attention to cooling capacity and noise, special attention should be paid to weight, vibration and power consumption.
As a modified caravan, we know that the lighter the curb weight, the better, and Europe has always been at the forefront in terms of lightweight. As the overhead air conditioner is installed on the roof, it is necessary to consider the roof load-bearing problem. On the one hand, the lightweight air conditioner can reduce vibration, and on the other hand, the low air conditioner can also reduce the center of gravity of the vehicle body and reduce wind resistance; from the perspective of safety, vehicles with a high center of gravity are prone to rollover when turning, and must be driven at a speed limit.
There is a certain correlation between vibration and noise. If the compressor, condenser, evaporator and fan are all completely fixed on the air conditioner base, the noise of the compressor will be alleviated to a certain extent when it is working, but the vibration during operation will be transmitted to the whole vehicle through the roof, which requires finding a suitable combination point between vibration and noise.
Four common questions about RV air conditioners
1. Question: Can household variable frequency air conditioners be used in RVs?
Answer: It depends on the situation, generally not.
Because the design premise of household air conditioners is fixed, and the vehicle is moving and bumpy, the seismic resistance level of household air conditioners cannot meet the requirements of vehicle driving. After long-term use, the components of the air conditioner will loosen and deform during vehicle driving, causing great hidden dangers to the safety of users' lives and property.
2. Question: What is the voltage of the parking air conditioner? What kind of electricity is used? Can the parking air conditioner use the power of the auxiliary battery in the car?
Answer: The input voltage of the common parking air conditioner in China is 220V. Whether abroad or in China, there are only two ways to use the power of the parking air conditioner in RVs produced by regular modification factories:
1) External 220V AC power supply;
2) Generator power supply.
The parking air conditioner cannot use the power of the auxiliary battery in the car. The common safety auxiliary battery in RVs is a maintenance-free battery. The use of high-power parking air conditioners will cause excessive discharge of the battery and occupy space in the car. Excessive increase in battery capacity will reduce vehicle performance and is not advisable.
3. Question: What is the cooling and heating power of the parking air conditioner? What power generator should be matched?
Answer: The answer is as follows.
The cooling power of a single cooling air conditioner is about 1000W, and it can be matched with a 1600W generator.
The heating power of the hot and cold air conditioner is about 2200W, and the power when starting the cooling is also 2300 watts. The cooling start time is about 10 minutes, and the power when the cooling is running is 1200W. The generator that matches the 2200W power of the hot and cold air conditioner should be 2600W-3000W.
4. Question: How to cool down without a generator?
Answer: There are two ways to cool down.
1) When the RV is parked, try to choose a safe place that can be connected to the mains.
2) If you go to a wild place, you can't connect to the electricity, and you don't have a generator, you can choose to use a micro fan to cool down.
