Mission Inn Hotel & Spa, RIVERSIDE, CA
HVAC Retrofit Services
MESA ENERGY SYSTEMS VALUE DELIVERED
Flexible HVAC design/build options; expanded cooling and electrical service capabilities; improved HVAC energy efficiency; reduced water consumption; historic preservation; minimal disruption of day-to-day business enabling continuous delivery of high-quality guest services; accelerated regulatory approvals and fast-track mechanical construction project completion; increased capacity for business growth.
MECHANICAL, ELECTRICAL & AC SERVICES OBJECTIVES
To support critical current and future business needs by increasing air-conditioning capacity and efficiency, and upgrading electrical service; to obtain an Energy Star rating.
HVAC DESIGN/BUILD & RETROFIT SOLUTIONS
To help this client meet its demanding commercial HVAC energy saving objectives, Mesa provided a high-performance HVAC design/build solution on a fast-track schedule. In addition to having maintained the client's existing plant for many years, Mesa was chosen for this project because, as a HVAC design/build firm, the company offered more and better options than the single-source solutions proposed by two HVAC manufacturers.
More efficient cooling system, less space
Mesa's HVAC retrofit solution involved replacing the hotel's 350-ton industrial chiller plant with a more efficient 600-ton modular unit and performing a major electrical upgrade. In addition to accommodating the mechanical construction project's fast-track delivery, the modular approach helped maintain the hotel's historic character, minimized the central chiller plant's footprint and allowed room for future needs.
The central plant was pre-built by the manufacturer, shipped in two sections and assembled on-site. The plant consisted of two centrifugal water-cooled chillers with factory-mounted variable-flow drives, and 2 two-cell stainless steel cooling towers with induced-draft, counterflow design, capable of cooling 2,000 gallons of water per minute. The plant also included chilled and condenser water pumps with variable speed drives, a cooling tower filtration and chemical feed system, a chilled water system expansion tank and air separator, two electric fan coil units for central plant air conditioning and a ventilation fan with gravity back-draft damper. A central plant industrial refrigerant monitoring system, a magnetic flow meter for monitoring the flow of main chilled water distribution and six automated isolation control valves completed the package.
Project delivery with no loose ends
In managing the project, Mesa made sure it took care of all the details. The company trenched new chilled water lines to an existing tunnel that led to the old chillers. It then installed new chilled water piping to -- and within -- the plant, as well as supply and return piping for the cooling towers. In addition, the company put in piping for chilled water, fan coil units and water treatment devices, and performed the various piping activities required to connect the chiller plant, the new cooling tower system and other equipment. The firm also installed a water source heat exchanger, which is part of the condenser loop. After completing the underground chilled and condenser water lines for the water source condensers, the company installed grade beams, structural pads and structural steel, so the towers could be set. The modular central chiller plant was then craned into place.
Cost-saving DDC system: BACnet
In addition, Mesa upgraded the plant's existing direct digital control (DDC) system to the BACnet protocol, enabling it to better handle the new commercial cooling equipment. This protocol significantly reduced installation costs of labor, conduit and wire. Rather than pulling wire from all components back to the main controller, the company simply pulled the wire to the closest controller, from which BACnet can relay information throughout the system.
Plenty of power today, plenty for tomorrow
The electrical renovation, which Mesa handled through its EMCOR sister company Dynalectric (Los Angeles, CA), was required because the Inn was severely underpowered. This became abundantly clear when the hotel's Festival of Lights, a major tourit attraction between Thanksgiving and New Year's Day, overloaded the facility's circuitry. To resolve this and other performance issues, the company worked with the local utilities to bring 3,000 amperes of 460-volt power to the central plant. Half of these amperes serve the central plant, and the parking garage lighting and exhaust system, while the other half has been reserved for future requirements. Finally, built-in redundancy further protects against downtime, while simplifying electrical maintenance.
Reaching for Energy Star
A number of the HVAC and industrial chiller installation's features will help the client meet another project objective -- to qualify for an Energy Star rating. For example, even with the additional capacity, the new plant will still use less power than the existing plant because of the variable speed drive technology, which dramatically reduces energy consumption at lower loads. In addition, the counterflow cooling towers use up to 45 percent less water than the existing system. And the inclusion of a side-stream separator keeps the condenser water cleaner. The commercial air conditioning system also uses R-134A refrigerant, which meets the U.S. Green Building Council's LEED certification standard.
As part of its continuing commercial HVAC maintenance contract, Mesa will benchmark the new cooling system's performance and participate in the Inn's ongoing efforts to reduce both water and power consumption.
Smooth on-time, within budget completion
Throughout the HVAC design/build services project, the company planned and scheduled carefully to minimize the impact on the Inn's guests and surrounding businesses. By working closely with the owner, local authorities and utilities, the architect, and subcontractors, Mesa was able to satisfy the city's stringent historic design criteria. At the same time, this collaborative approach shortened the usual historic review process from six to less than two weeks, a key factor in this fast-track mechanical construction project's successful completion. As a result, the company made a smooth transition from the old to the new commercial air conditioning system and initiated full system operation in time to meet the needs of the Inn's peak cooling season.
HOSPITALITY FACILITY BACKGROUND
The Mission Inn Hotel & Spa is a National Historic Landmark described by Will Rogers as "the most unique hotel in America." Begun in 1876 as a boarding house, it now occupies an entire city block. Its multiple wings reflect architectural styles and furnishings ranging from the New World to the Far East. There are 239 guest rooms, including 28 suites, as well as 20,000 square feet of meeting and banquet space, a full-service spa and four restaurants.